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<html><head><title>Python: module novas.compat</title>
</head><body bgcolor="#f0f0f8">

<table width="100%" cellspacing=0 cellpadding=2 border=0 summary="heading">
<tr bgcolor="#7799ee">
<td valign=bottom>&nbsp;<br>
<font color="#ffffff" face="helvetica, arial">&nbsp;<br><big><big><strong>novas.compat</strong></big></big></font></td
></tr></table>
<p>
<table width="100%" cellspacing=0 cellpadding=2 border=0 summary="section">
<tr bgcolor="#ee77aa">
<td colspan=3 valign=bottom>&nbsp;<br>
<font color="#ffffff" face="helvetica, arial"><big><strong>Classes</strong></big></font></td></tr>
    
<tr><td bgcolor="#ee77aa"><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</tt></td><td>&nbsp;</td>
<td width="100%"><dl>
<dt><font face="helvetica, arial"><a href="_ctypes.html#Structure">_ctypes.Structure</a>(_ctypes._CData)
</font></dt><dd>
<dl>
<dt><font face="helvetica, arial"><a href="novas.compat.compat.html#CatEntry">CatEntry</a>
</font></dt><dt><font face="helvetica, arial"><a href="novas.compat.compat.html#InSpace">InSpace</a>
</font></dt><dt><font face="helvetica, arial"><a href="novas.compat.compat.html#Object">Object</a>
</font></dt><dt><font face="helvetica, arial"><a href="novas.compat.compat.html#Observer">Observer</a>
</font></dt><dt><font face="helvetica, arial"><a href="novas.compat.compat.html#OnSurface">OnSurface</a>
</font></dt><dt><font face="helvetica, arial"><a href="novas.compat.compat.html#RAofCIO">RAofCIO</a>
</font></dt><dt><font face="helvetica, arial"><a href="novas.compat.compat.html#SkyPos">SkyPos</a>
</font></dt></dl>
</dd>
</dl>
 <p>
<table width="100%" cellspacing=0 cellpadding=2 border=0 summary="section">
<tr bgcolor="#ffc8d8">
<td colspan=3 valign=bottom>&nbsp;<br>
<font color="#000000" face="helvetica, arial"><a name="CatEntry">class <strong>CatEntry</strong></a>(<a href="_ctypes.html#Structure">_ctypes.Structure</a>)</font></td></tr>
    
<tr><td bgcolor="#ffc8d8"><tt>&nbsp;&nbsp;&nbsp;</tt></td><td>&nbsp;</td>
<td width="100%"><dl><dt>Method resolution order:</dt>
<dd><a href="novas.compat.compat.html#CatEntry">CatEntry</a></dd>
<dd><a href="_ctypes.html#Structure">_ctypes.Structure</a></dd>
<dd>_ctypes._CData</dd>
<dd><a href="__builtin__.html#object">__builtin__.object</a></dd>
</dl>
<hr>
Data descriptors defined here:<br>
<dl><dt><strong>__dict__</strong></dt>
<dd><tt>dictionary&nbsp;for&nbsp;instance&nbsp;variables&nbsp;(if&nbsp;defined)</tt></dd>
</dl>
<dl><dt><strong>__weakref__</strong></dt>
<dd><tt>list&nbsp;of&nbsp;weak&nbsp;references&nbsp;to&nbsp;the&nbsp;object&nbsp;(if&nbsp;defined)</tt></dd>
</dl>
<dl><dt><strong>catalog</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>dec</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>parallax</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>promodec</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>promora</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>ra</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>radialvelocity</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>starname</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>starnumber</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<hr>
Methods inherited from <a href="_ctypes.html#Structure">_ctypes.Structure</a>:<br>
<dl><dt><a name="CatEntry-__init__"><strong>__init__</strong></a>(...)</dt><dd><tt>x.<a href="#CatEntry-__init__">__init__</a>(...)&nbsp;initializes&nbsp;x;&nbsp;see&nbsp;help(type(x))&nbsp;for&nbsp;signature</tt></dd></dl>

<hr>
Data and other attributes inherited from <a href="_ctypes.html#Structure">_ctypes.Structure</a>:<br>
<dl><dt><strong>__new__</strong> = &lt;built-in method __new__ of _ctypes.PyCStructType object&gt;<dd><tt>T.<a href="#CatEntry-__new__">__new__</a>(S,&nbsp;...)&nbsp;-&gt;&nbsp;a&nbsp;new&nbsp;object&nbsp;with&nbsp;type&nbsp;S,&nbsp;a&nbsp;subtype&nbsp;of&nbsp;T</tt></dl>

<hr>
Methods inherited from _ctypes._CData:<br>
<dl><dt><a name="CatEntry-__ctypes_from_outparam__"><strong>__ctypes_from_outparam__</strong></a>(...)</dt></dl>

<dl><dt><a name="CatEntry-__hash__"><strong>__hash__</strong></a>(...)</dt><dd><tt>x.<a href="#CatEntry-__hash__">__hash__</a>()&nbsp;&lt;==&gt;&nbsp;hash(x)</tt></dd></dl>

<dl><dt><a name="CatEntry-__reduce__"><strong>__reduce__</strong></a>(...)</dt></dl>

<dl><dt><a name="CatEntry-__setstate__"><strong>__setstate__</strong></a>(...)</dt></dl>

</td></tr></table> <p>
<table width="100%" cellspacing=0 cellpadding=2 border=0 summary="section">
<tr bgcolor="#ffc8d8">
<td colspan=3 valign=bottom>&nbsp;<br>
<font color="#000000" face="helvetica, arial"><a name="InSpace">class <strong>InSpace</strong></a>(<a href="_ctypes.html#Structure">_ctypes.Structure</a>)</font></td></tr>
    
<tr><td bgcolor="#ffc8d8"><tt>&nbsp;&nbsp;&nbsp;</tt></td><td>&nbsp;</td>
<td width="100%"><dl><dt>Method resolution order:</dt>
<dd><a href="novas.compat.compat.html#InSpace">InSpace</a></dd>
<dd><a href="_ctypes.html#Structure">_ctypes.Structure</a></dd>
<dd>_ctypes._CData</dd>
<dd><a href="__builtin__.html#object">__builtin__.object</a></dd>
</dl>
<hr>
Data descriptors defined here:<br>
<dl><dt><strong>__dict__</strong></dt>
<dd><tt>dictionary&nbsp;for&nbsp;instance&nbsp;variables&nbsp;(if&nbsp;defined)</tt></dd>
</dl>
<dl><dt><strong>__weakref__</strong></dt>
<dd><tt>list&nbsp;of&nbsp;weak&nbsp;references&nbsp;to&nbsp;the&nbsp;object&nbsp;(if&nbsp;defined)</tt></dd>
</dl>
<dl><dt><strong>sc_pos</strong></dt>
</dl>
<dl><dt><strong>sc_vel</strong></dt>
</dl>
<hr>
Methods inherited from <a href="_ctypes.html#Structure">_ctypes.Structure</a>:<br>
<dl><dt><a name="InSpace-__init__"><strong>__init__</strong></a>(...)</dt><dd><tt>x.<a href="#InSpace-__init__">__init__</a>(...)&nbsp;initializes&nbsp;x;&nbsp;see&nbsp;help(type(x))&nbsp;for&nbsp;signature</tt></dd></dl>

<hr>
Data and other attributes inherited from <a href="_ctypes.html#Structure">_ctypes.Structure</a>:<br>
<dl><dt><strong>__new__</strong> = &lt;built-in method __new__ of _ctypes.PyCStructType object&gt;<dd><tt>T.<a href="#InSpace-__new__">__new__</a>(S,&nbsp;...)&nbsp;-&gt;&nbsp;a&nbsp;new&nbsp;object&nbsp;with&nbsp;type&nbsp;S,&nbsp;a&nbsp;subtype&nbsp;of&nbsp;T</tt></dl>

<hr>
Methods inherited from _ctypes._CData:<br>
<dl><dt><a name="InSpace-__ctypes_from_outparam__"><strong>__ctypes_from_outparam__</strong></a>(...)</dt></dl>

<dl><dt><a name="InSpace-__hash__"><strong>__hash__</strong></a>(...)</dt><dd><tt>x.<a href="#InSpace-__hash__">__hash__</a>()&nbsp;&lt;==&gt;&nbsp;hash(x)</tt></dd></dl>

<dl><dt><a name="InSpace-__reduce__"><strong>__reduce__</strong></a>(...)</dt></dl>

<dl><dt><a name="InSpace-__setstate__"><strong>__setstate__</strong></a>(...)</dt></dl>

</td></tr></table> <p>
<table width="100%" cellspacing=0 cellpadding=2 border=0 summary="section">
<tr bgcolor="#ffc8d8">
<td colspan=3 valign=bottom>&nbsp;<br>
<font color="#000000" face="helvetica, arial"><a name="Object">class <strong>Object</strong></a>(<a href="_ctypes.html#Structure">_ctypes.Structure</a>)</font></td></tr>
    
<tr><td bgcolor="#ffc8d8"><tt>&nbsp;&nbsp;&nbsp;</tt></td><td>&nbsp;</td>
<td width="100%"><dl><dt>Method resolution order:</dt>
<dd><a href="novas.compat.compat.html#Object">Object</a></dd>
<dd><a href="_ctypes.html#Structure">_ctypes.Structure</a></dd>
<dd>_ctypes._CData</dd>
<dd><a href="__builtin__.html#object">__builtin__.object</a></dd>
</dl>
<hr>
Data descriptors defined here:<br>
<dl><dt><strong>__dict__</strong></dt>
<dd><tt>dictionary&nbsp;for&nbsp;instance&nbsp;variables&nbsp;(if&nbsp;defined)</tt></dd>
</dl>
<dl><dt><strong>__weakref__</strong></dt>
<dd><tt>list&nbsp;of&nbsp;weak&nbsp;references&nbsp;to&nbsp;the&nbsp;object&nbsp;(if&nbsp;defined)</tt></dd>
</dl>
<dl><dt><strong>name</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>number</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>star</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>type</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<hr>
Methods inherited from <a href="_ctypes.html#Structure">_ctypes.Structure</a>:<br>
<dl><dt><a name="Object-__init__"><strong>__init__</strong></a>(...)</dt><dd><tt>x.<a href="#Object-__init__">__init__</a>(...)&nbsp;initializes&nbsp;x;&nbsp;see&nbsp;help(<a href="#Object-type">type</a>(x))&nbsp;for&nbsp;signature</tt></dd></dl>

<hr>
Data and other attributes inherited from <a href="_ctypes.html#Structure">_ctypes.Structure</a>:<br>
<dl><dt><strong>__new__</strong> = &lt;built-in method __new__ of _ctypes.PyCStructType object&gt;<dd><tt>T.<a href="#Object-__new__">__new__</a>(S,&nbsp;...)&nbsp;-&gt;&nbsp;a&nbsp;new&nbsp;object&nbsp;with&nbsp;type&nbsp;S,&nbsp;a&nbsp;subtype&nbsp;of&nbsp;T</tt></dl>

<hr>
Methods inherited from _ctypes._CData:<br>
<dl><dt><a name="Object-__ctypes_from_outparam__"><strong>__ctypes_from_outparam__</strong></a>(...)</dt></dl>

<dl><dt><a name="Object-__hash__"><strong>__hash__</strong></a>(...)</dt><dd><tt>x.<a href="#Object-__hash__">__hash__</a>()&nbsp;&lt;==&gt;&nbsp;hash(x)</tt></dd></dl>

<dl><dt><a name="Object-__reduce__"><strong>__reduce__</strong></a>(...)</dt></dl>

<dl><dt><a name="Object-__setstate__"><strong>__setstate__</strong></a>(...)</dt></dl>

</td></tr></table> <p>
<table width="100%" cellspacing=0 cellpadding=2 border=0 summary="section">
<tr bgcolor="#ffc8d8">
<td colspan=3 valign=bottom>&nbsp;<br>
<font color="#000000" face="helvetica, arial"><a name="Observer">class <strong>Observer</strong></a>(<a href="_ctypes.html#Structure">_ctypes.Structure</a>)</font></td></tr>
    
<tr><td bgcolor="#ffc8d8"><tt>&nbsp;&nbsp;&nbsp;</tt></td><td>&nbsp;</td>
<td width="100%"><dl><dt>Method resolution order:</dt>
<dd><a href="novas.compat.compat.html#Observer">Observer</a></dd>
<dd><a href="_ctypes.html#Structure">_ctypes.Structure</a></dd>
<dd>_ctypes._CData</dd>
<dd><a href="__builtin__.html#object">__builtin__.object</a></dd>
</dl>
<hr>
Data descriptors defined here:<br>
<dl><dt><strong>__dict__</strong></dt>
<dd><tt>dictionary&nbsp;for&nbsp;instance&nbsp;variables&nbsp;(if&nbsp;defined)</tt></dd>
</dl>
<dl><dt><strong>__weakref__</strong></dt>
<dd><tt>list&nbsp;of&nbsp;weak&nbsp;references&nbsp;to&nbsp;the&nbsp;object&nbsp;(if&nbsp;defined)</tt></dd>
</dl>
<dl><dt><strong>near_earth</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>on_surf</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>where</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<hr>
Methods inherited from <a href="_ctypes.html#Structure">_ctypes.Structure</a>:<br>
<dl><dt><a name="Observer-__init__"><strong>__init__</strong></a>(...)</dt><dd><tt>x.<a href="#Observer-__init__">__init__</a>(...)&nbsp;initializes&nbsp;x;&nbsp;see&nbsp;help(type(x))&nbsp;for&nbsp;signature</tt></dd></dl>

<hr>
Data and other attributes inherited from <a href="_ctypes.html#Structure">_ctypes.Structure</a>:<br>
<dl><dt><strong>__new__</strong> = &lt;built-in method __new__ of _ctypes.PyCStructType object&gt;<dd><tt>T.<a href="#Observer-__new__">__new__</a>(S,&nbsp;...)&nbsp;-&gt;&nbsp;a&nbsp;new&nbsp;object&nbsp;with&nbsp;type&nbsp;S,&nbsp;a&nbsp;subtype&nbsp;of&nbsp;T</tt></dl>

<hr>
Methods inherited from _ctypes._CData:<br>
<dl><dt><a name="Observer-__ctypes_from_outparam__"><strong>__ctypes_from_outparam__</strong></a>(...)</dt></dl>

<dl><dt><a name="Observer-__hash__"><strong>__hash__</strong></a>(...)</dt><dd><tt>x.<a href="#Observer-__hash__">__hash__</a>()&nbsp;&lt;==&gt;&nbsp;hash(x)</tt></dd></dl>

<dl><dt><a name="Observer-__reduce__"><strong>__reduce__</strong></a>(...)</dt></dl>

<dl><dt><a name="Observer-__setstate__"><strong>__setstate__</strong></a>(...)</dt></dl>

</td></tr></table> <p>
<table width="100%" cellspacing=0 cellpadding=2 border=0 summary="section">
<tr bgcolor="#ffc8d8">
<td colspan=3 valign=bottom>&nbsp;<br>
<font color="#000000" face="helvetica, arial"><a name="OnSurface">class <strong>OnSurface</strong></a>(<a href="_ctypes.html#Structure">_ctypes.Structure</a>)</font></td></tr>
    
<tr><td bgcolor="#ffc8d8"><tt>&nbsp;&nbsp;&nbsp;</tt></td><td>&nbsp;</td>
<td width="100%"><dl><dt>Method resolution order:</dt>
<dd><a href="novas.compat.compat.html#OnSurface">OnSurface</a></dd>
<dd><a href="_ctypes.html#Structure">_ctypes.Structure</a></dd>
<dd>_ctypes._CData</dd>
<dd><a href="__builtin__.html#object">__builtin__.object</a></dd>
</dl>
<hr>
Data descriptors defined here:<br>
<dl><dt><strong>__dict__</strong></dt>
<dd><tt>dictionary&nbsp;for&nbsp;instance&nbsp;variables&nbsp;(if&nbsp;defined)</tt></dd>
</dl>
<dl><dt><strong>__weakref__</strong></dt>
<dd><tt>list&nbsp;of&nbsp;weak&nbsp;references&nbsp;to&nbsp;the&nbsp;object&nbsp;(if&nbsp;defined)</tt></dd>
</dl>
<dl><dt><strong>height</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>latitude</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>longitude</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>pressure</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>temperature</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<hr>
Methods inherited from <a href="_ctypes.html#Structure">_ctypes.Structure</a>:<br>
<dl><dt><a name="OnSurface-__init__"><strong>__init__</strong></a>(...)</dt><dd><tt>x.<a href="#OnSurface-__init__">__init__</a>(...)&nbsp;initializes&nbsp;x;&nbsp;see&nbsp;help(type(x))&nbsp;for&nbsp;signature</tt></dd></dl>

<hr>
Data and other attributes inherited from <a href="_ctypes.html#Structure">_ctypes.Structure</a>:<br>
<dl><dt><strong>__new__</strong> = &lt;built-in method __new__ of _ctypes.PyCStructType object&gt;<dd><tt>T.<a href="#OnSurface-__new__">__new__</a>(S,&nbsp;...)&nbsp;-&gt;&nbsp;a&nbsp;new&nbsp;object&nbsp;with&nbsp;type&nbsp;S,&nbsp;a&nbsp;subtype&nbsp;of&nbsp;T</tt></dl>

<hr>
Methods inherited from _ctypes._CData:<br>
<dl><dt><a name="OnSurface-__ctypes_from_outparam__"><strong>__ctypes_from_outparam__</strong></a>(...)</dt></dl>

<dl><dt><a name="OnSurface-__hash__"><strong>__hash__</strong></a>(...)</dt><dd><tt>x.<a href="#OnSurface-__hash__">__hash__</a>()&nbsp;&lt;==&gt;&nbsp;hash(x)</tt></dd></dl>

<dl><dt><a name="OnSurface-__reduce__"><strong>__reduce__</strong></a>(...)</dt></dl>

<dl><dt><a name="OnSurface-__setstate__"><strong>__setstate__</strong></a>(...)</dt></dl>

</td></tr></table> <p>
<table width="100%" cellspacing=0 cellpadding=2 border=0 summary="section">
<tr bgcolor="#ffc8d8">
<td colspan=3 valign=bottom>&nbsp;<br>
<font color="#000000" face="helvetica, arial"><a name="RAofCIO">class <strong>RAofCIO</strong></a>(<a href="_ctypes.html#Structure">_ctypes.Structure</a>)</font></td></tr>
    
<tr><td bgcolor="#ffc8d8"><tt>&nbsp;&nbsp;&nbsp;</tt></td><td>&nbsp;</td>
<td width="100%"><dl><dt>Method resolution order:</dt>
<dd><a href="novas.compat.compat.html#RAofCIO">RAofCIO</a></dd>
<dd><a href="_ctypes.html#Structure">_ctypes.Structure</a></dd>
<dd>_ctypes._CData</dd>
<dd><a href="__builtin__.html#object">__builtin__.object</a></dd>
</dl>
<hr>
Data descriptors defined here:<br>
<dl><dt><strong>__dict__</strong></dt>
<dd><tt>dictionary&nbsp;for&nbsp;instance&nbsp;variables&nbsp;(if&nbsp;defined)</tt></dd>
</dl>
<dl><dt><strong>__weakref__</strong></dt>
<dd><tt>list&nbsp;of&nbsp;weak&nbsp;references&nbsp;to&nbsp;the&nbsp;object&nbsp;(if&nbsp;defined)</tt></dd>
</dl>
<dl><dt><strong>jd_tdb</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>ra_cio</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<hr>
Methods inherited from <a href="_ctypes.html#Structure">_ctypes.Structure</a>:<br>
<dl><dt><a name="RAofCIO-__init__"><strong>__init__</strong></a>(...)</dt><dd><tt>x.<a href="#RAofCIO-__init__">__init__</a>(...)&nbsp;initializes&nbsp;x;&nbsp;see&nbsp;help(type(x))&nbsp;for&nbsp;signature</tt></dd></dl>

<hr>
Data and other attributes inherited from <a href="_ctypes.html#Structure">_ctypes.Structure</a>:<br>
<dl><dt><strong>__new__</strong> = &lt;built-in method __new__ of _ctypes.PyCStructType object&gt;<dd><tt>T.<a href="#RAofCIO-__new__">__new__</a>(S,&nbsp;...)&nbsp;-&gt;&nbsp;a&nbsp;new&nbsp;object&nbsp;with&nbsp;type&nbsp;S,&nbsp;a&nbsp;subtype&nbsp;of&nbsp;T</tt></dl>

<hr>
Methods inherited from _ctypes._CData:<br>
<dl><dt><a name="RAofCIO-__ctypes_from_outparam__"><strong>__ctypes_from_outparam__</strong></a>(...)</dt></dl>

<dl><dt><a name="RAofCIO-__hash__"><strong>__hash__</strong></a>(...)</dt><dd><tt>x.<a href="#RAofCIO-__hash__">__hash__</a>()&nbsp;&lt;==&gt;&nbsp;hash(x)</tt></dd></dl>

<dl><dt><a name="RAofCIO-__reduce__"><strong>__reduce__</strong></a>(...)</dt></dl>

<dl><dt><a name="RAofCIO-__setstate__"><strong>__setstate__</strong></a>(...)</dt></dl>

</td></tr></table> <p>
<table width="100%" cellspacing=0 cellpadding=2 border=0 summary="section">
<tr bgcolor="#ffc8d8">
<td colspan=3 valign=bottom>&nbsp;<br>
<font color="#000000" face="helvetica, arial"><a name="SkyPos">class <strong>SkyPos</strong></a>(<a href="_ctypes.html#Structure">_ctypes.Structure</a>)</font></td></tr>
    
<tr><td bgcolor="#ffc8d8"><tt>&nbsp;&nbsp;&nbsp;</tt></td><td>&nbsp;</td>
<td width="100%"><dl><dt>Method resolution order:</dt>
<dd><a href="novas.compat.compat.html#SkyPos">SkyPos</a></dd>
<dd><a href="_ctypes.html#Structure">_ctypes.Structure</a></dd>
<dd>_ctypes._CData</dd>
<dd><a href="__builtin__.html#object">__builtin__.object</a></dd>
</dl>
<hr>
Data descriptors defined here:<br>
<dl><dt><strong>__dict__</strong></dt>
<dd><tt>dictionary&nbsp;for&nbsp;instance&nbsp;variables&nbsp;(if&nbsp;defined)</tt></dd>
</dl>
<dl><dt><strong>__weakref__</strong></dt>
<dd><tt>list&nbsp;of&nbsp;weak&nbsp;references&nbsp;to&nbsp;the&nbsp;object&nbsp;(if&nbsp;defined)</tt></dd>
</dl>
<dl><dt><strong>dec</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>dis</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>r_hat</strong></dt>
</dl>
<dl><dt><strong>ra</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<dl><dt><strong>rv</strong></dt>
<dd><tt>Structure/Union&nbsp;member</tt></dd>
</dl>
<hr>
Methods inherited from <a href="_ctypes.html#Structure">_ctypes.Structure</a>:<br>
<dl><dt><a name="SkyPos-__init__"><strong>__init__</strong></a>(...)</dt><dd><tt>x.<a href="#SkyPos-__init__">__init__</a>(...)&nbsp;initializes&nbsp;x;&nbsp;see&nbsp;help(type(x))&nbsp;for&nbsp;signature</tt></dd></dl>

<hr>
Data and other attributes inherited from <a href="_ctypes.html#Structure">_ctypes.Structure</a>:<br>
<dl><dt><strong>__new__</strong> = &lt;built-in method __new__ of _ctypes.PyCStructType object&gt;<dd><tt>T.<a href="#SkyPos-__new__">__new__</a>(S,&nbsp;...)&nbsp;-&gt;&nbsp;a&nbsp;new&nbsp;object&nbsp;with&nbsp;type&nbsp;S,&nbsp;a&nbsp;subtype&nbsp;of&nbsp;T</tt></dl>

<hr>
Methods inherited from _ctypes._CData:<br>
<dl><dt><a name="SkyPos-__ctypes_from_outparam__"><strong>__ctypes_from_outparam__</strong></a>(...)</dt></dl>

<dl><dt><a name="SkyPos-__hash__"><strong>__hash__</strong></a>(...)</dt><dd><tt>x.<a href="#SkyPos-__hash__">__hash__</a>()&nbsp;&lt;==&gt;&nbsp;hash(x)</tt></dd></dl>

<dl><dt><a name="SkyPos-__reduce__"><strong>__reduce__</strong></a>(...)</dt></dl>

<dl><dt><a name="SkyPos-__setstate__"><strong>__setstate__</strong></a>(...)</dt></dl>

</td></tr></table></td></tr></table><p>
<table width="100%" cellspacing=0 cellpadding=2 border=0 summary="section">
<tr bgcolor="#eeaa77">
<td colspan=3 valign=bottom>&nbsp;<br>
<font color="#ffffff" face="helvetica, arial"><big><strong>Functions</strong></big></font></td></tr>
    
<tr><td bgcolor="#eeaa77"><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</tt></td><td>&nbsp;</td>
<td width="100%"><dl><dt><a name="-POINTER"><strong>POINTER</strong></a>(...)</dt></dl>
 <dl><dt><a name="-aberration"><strong>aberration</strong></a>(position, vel_earth, lighttime)</dt><dd><tt>Correct&nbsp;the&nbsp;position&nbsp;vector&nbsp;for&nbsp;aberration&nbsp;of&nbsp;light,&nbsp;including<br>
relativistic&nbsp;terms.<br>
&nbsp;<br>
Parameters<br>
----------<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;referred&nbsp;to&nbsp;origin&nbsp;at&nbsp;center&nbsp;of&nbsp;mass&nbsp;of&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;Earth,&nbsp;components&nbsp;in&nbsp;AU.<br>
vel_earth&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Velocity&nbsp;vector&nbsp;of&nbsp;center&nbsp;of&nbsp;mass&nbsp;of&nbsp;the&nbsp;Earth,&nbsp;referred&nbsp;to<br>
&nbsp;&nbsp;&nbsp;&nbsp;origin&nbsp;at&nbsp;solar&nbsp;system&nbsp;barycenter,&nbsp;components&nbsp;in&nbsp;AU/day.<br>
lighttime&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Light&nbsp;time&nbsp;from&nbsp;object&nbsp;to&nbsp;Earth&nbsp;in&nbsp;days.<br>
&nbsp;<br>
Returns<br>
-------<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;referred&nbsp;to&nbsp;origin&nbsp;at&nbsp;center&nbsp;of&nbsp;mass&nbsp;of&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;Earth,&nbsp;corrected&nbsp;for&nbsp;aberration,&nbsp;components&nbsp;in&nbsp;AU.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;If&nbsp;'lighttime'&nbsp;=&nbsp;0&nbsp;on&nbsp;input,&nbsp;this&nbsp;function&nbsp;will&nbsp;compute&nbsp;it.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Murray,&nbsp;C.&nbsp;A.&nbsp;(1981)&nbsp;Mon.&nbsp;Notices&nbsp;Royal&nbsp;Ast.&nbsp;Society&nbsp;195,<br>
&nbsp;&nbsp;&nbsp;&nbsp;639-648.</tt></dd></dl>
 <dl><dt><a name="-addressof"><strong>addressof</strong></a>(...)</dt><dd><tt><a href="#-addressof">addressof</a>(C&nbsp;instance)&nbsp;-&gt;&nbsp;integer<br>
Return&nbsp;the&nbsp;address&nbsp;of&nbsp;the&nbsp;C&nbsp;instance&nbsp;internal&nbsp;buffer</tt></dd></dl>
 <dl><dt><a name="-alignment"><strong>alignment</strong></a>(...)</dt><dd><tt><a href="#-alignment">alignment</a>(C&nbsp;type)&nbsp;-&gt;&nbsp;integer<br>
<a href="#-alignment">alignment</a>(C&nbsp;instance)&nbsp;-&gt;&nbsp;integer<br>
Return&nbsp;the&nbsp;alignment&nbsp;requirements&nbsp;of&nbsp;a&nbsp;C&nbsp;instance</tt></dd></dl>
 <dl><dt><a name="-app_planet"><strong>app_planet</strong></a>(jd_tt, ss_body, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Compute&nbsp;the&nbsp;apparent&nbsp;place&nbsp;of&nbsp;a&nbsp;planet&nbsp;or&nbsp;other&nbsp;solar&nbsp;system&nbsp;body.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date&nbsp;for&nbsp;apparent&nbsp;place.<br>
ss_body&nbsp;:&nbsp;<a href="#Object">Object</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#Object">Object</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;the&nbsp;body&nbsp;designation<br>
&nbsp;&nbsp;&nbsp;&nbsp;for&nbsp;the&nbsp;solar&nbsp;system&nbsp;body.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(ra,&nbsp;dec,&nbsp;dis)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Apparent&nbsp;(right&nbsp;ascension&nbsp;in&nbsp;hours,&nbsp;declination&nbsp;in&nbsp;degrees,<br>
&nbsp;&nbsp;&nbsp;&nbsp;...),<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;true&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date,&nbsp;and&nbsp;true<br>
&nbsp;&nbsp;&nbsp;&nbsp;(...,&nbsp;...,&nbsp;distance&nbsp;in&nbsp;AU)&nbsp;from&nbsp;Earth&nbsp;to&nbsp;solar&nbsp;system&nbsp;body&nbsp;at<br>
&nbsp;&nbsp;&nbsp;&nbsp;'jd_tt'.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C67.<br>
..&nbsp;[R2]&nbsp;Explanatory&nbsp;Supplement&nbsp;to&nbsp;the&nbsp;Astronomical&nbsp;Almanac&nbsp;(1992),<br>
&nbsp;&nbsp;&nbsp;&nbsp;Chapter&nbsp;3.</tt></dd></dl>
 <dl><dt><a name="-app_star"><strong>app_star</strong></a>(jd_tt, star, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Computes&nbsp;the&nbsp;apparent&nbsp;place&nbsp;of&nbsp;a&nbsp;star&nbsp;at&nbsp;'date',&nbsp;given&nbsp;its&nbsp;catalog<br>
mean&nbsp;place,&nbsp;proper&nbsp;motion,&nbsp;parallax,&nbsp;and&nbsp;radial&nbsp;velocity.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date&nbsp;for&nbsp;apparent&nbsp;place.<br>
star&nbsp;:&nbsp;<a href="#CatEntry">CatEntry</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#CatEntry">CatEntry</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;catalog&nbsp;data&nbsp;for<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;object&nbsp;in&nbsp;the&nbsp;ICRS.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(ra,&nbsp;dec)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Apparent&nbsp;(right&nbsp;ascension&nbsp;in&nbsp;hours,&nbsp;declination&nbsp;in&nbsp;degrees),<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;true&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date&nbsp;'jd_tt'.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C61.<br>
..&nbsp;[R2]&nbsp;Explanatory&nbsp;Supplement&nbsp;to&nbsp;the&nbsp;Astronomical&nbsp;Almanac&nbsp;(1992),<br>
&nbsp;&nbsp;&nbsp;&nbsp;Chapter&nbsp;3.</tt></dd></dl>
 <dl><dt><a name="-astro_planet"><strong>astro_planet</strong></a>(jd_tt, ss_body, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Compute&nbsp;the&nbsp;astrometric&nbsp;place&nbsp;of&nbsp;a&nbsp;planet&nbsp;or&nbsp;other&nbsp;solar&nbsp;system<br>
body.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date&nbsp;for&nbsp;astrometric&nbsp;place.<br>
ss_body&nbsp;:&nbsp;<a href="#Object">Object</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#Object">Object</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;the&nbsp;body&nbsp;designation<br>
&nbsp;&nbsp;&nbsp;&nbsp;for&nbsp;the&nbsp;solar&nbsp;system&nbsp;body.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(ra,&nbsp;dec,&nbsp;dis)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Astrometric&nbsp;(right&nbsp;ascension&nbsp;in&nbsp;hours,&nbsp;declination&nbsp;in&nbsp;degrees,<br>
&nbsp;&nbsp;&nbsp;&nbsp;...),&nbsp;referred&nbsp;to&nbsp;the&nbsp;ICRS&nbsp;without&nbsp;light&nbsp;deflection&nbsp;or<br>
&nbsp;&nbsp;&nbsp;&nbsp;aberration,&nbsp;and&nbsp;true&nbsp;(...,&nbsp;...,&nbsp;distance&nbsp;in&nbsp;AU)&nbsp;from&nbsp;Earth&nbsp;to<br>
&nbsp;&nbsp;&nbsp;&nbsp;solar&nbsp;system&nbsp;body.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C73.<br>
..&nbsp;[R2]&nbsp;Explanatory&nbsp;Supplement&nbsp;to&nbsp;the&nbsp;Astronomical&nbsp;Almanac&nbsp;(1992),<br>
&nbsp;&nbsp;&nbsp;&nbsp;Chapter&nbsp;3.</tt></dd></dl>
 <dl><dt><a name="-astro_star"><strong>astro_star</strong></a>(jd_tt, star, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Computes&nbsp;the&nbsp;astrometric&nbsp;place&nbsp;of&nbsp;a&nbsp;star&nbsp;at&nbsp;'date',&nbsp;given&nbsp;its&nbsp;<br>
catalog&nbsp;mean&nbsp;place,&nbsp;proper&nbsp;motion,&nbsp;parallax,&nbsp;and&nbsp;radial&nbsp;velocity.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date&nbsp;for&nbsp;astrometric&nbsp;place.<br>
star&nbsp;:&nbsp;<a href="#CatEntry">CatEntry</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#CatEntry">CatEntry</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;catalog&nbsp;data&nbsp;for<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;object&nbsp;in&nbsp;the&nbsp;ICRS.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(ra,&nbsp;dec)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Astrometric&nbsp;(right&nbsp;ascension&nbsp;in&nbsp;hours,&nbsp;declination&nbsp;in&nbsp;degrees),<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;the&nbsp;ICRS&nbsp;without&nbsp;light&nbsp;deflection&nbsp;or&nbsp;aberration.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C66.<br>
..&nbsp;[R2]&nbsp;Explanatory&nbsp;Supplement&nbsp;to&nbsp;the&nbsp;Astronomical&nbsp;Almanac&nbsp;(1992),<br>
&nbsp;&nbsp;&nbsp;&nbsp;Chapter&nbsp;3.</tt></dd></dl>
 <dl><dt><a name="-bary2obs"><strong>bary2obs</strong></a>(pos, pos_obs)</dt><dd><tt>Transform&nbsp;the&nbsp;origin&nbsp;from&nbsp;the&nbsp;solar&nbsp;system&nbsp;barycenter&nbsp;to&nbsp;the<br>
observer&nbsp;(or&nbsp;the&nbsp;geocenter);&nbsp;i.e.,&nbsp;correct&nbsp;for&nbsp;parallax<br>
(annual+geocentric&nbsp;or&nbsp;just&nbsp;annual).<br>
&nbsp;<br>
Parameters<br>
----------<br>
pos&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;referred&nbsp;to&nbsp;origin&nbsp;at&nbsp;solar&nbsp;system&nbsp;barycenter,<br>
&nbsp;&nbsp;&nbsp;&nbsp;components&nbsp;in&nbsp;AU.<br>
pos_obs&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;of&nbsp;observer&nbsp;(or&nbsp;the&nbsp;geocenter),&nbsp;with&nbsp;respect&nbsp;to<br>
&nbsp;&nbsp;&nbsp;&nbsp;origin&nbsp;at&nbsp;solar&nbsp;system&nbsp;barycenter,&nbsp;components&nbsp;in&nbsp;AU.<br>
&nbsp;<br>
Returns<br>
-------<br>
(position,&nbsp;lighttime)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;tuple&nbsp;and&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;referred&nbsp;to&nbsp;origin&nbsp;at&nbsp;center&nbsp;of&nbsp;mass&nbsp;of&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;Earth,&nbsp;components&nbsp;in&nbsp;AU,&nbsp;and&nbsp;lighttime&nbsp;of&nbsp;object&nbsp;from&nbsp;Earth&nbsp;in<br>
&nbsp;&nbsp;&nbsp;&nbsp;days.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C17,&nbsp;C109.</tt></dd></dl>
 <dl><dt><a name="-byref"><strong>byref</strong></a>(...)</dt><dd><tt><a href="#-byref">byref</a>(C&nbsp;instance[,&nbsp;offset=0])&nbsp;-&gt;&nbsp;byref-object<br>
Return&nbsp;a&nbsp;pointer&nbsp;lookalike&nbsp;to&nbsp;a&nbsp;C&nbsp;instance,&nbsp;only&nbsp;usable<br>
as&nbsp;function&nbsp;argument</tt></dd></dl>
 <dl><dt><a name="-cal_date"><strong>cal_date</strong></a>(day)</dt><dd><tt>Return&nbsp;the&nbsp;Gregorian&nbsp;date&nbsp;for&nbsp;a&nbsp;given&nbsp;Julian&nbsp;day.<br>
&nbsp;<br>
Parameters<br>
----------<br>
day&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Julian&nbsp;day.<br>
&nbsp;<br>
Returns<br>
-------<br>
date&nbsp;:&nbsp;tuple&nbsp;of&nbsp;three&nbsp;ints&nbsp;and&nbsp;a&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;The&nbsp;elements&nbsp;are&nbsp;year,&nbsp;month,&nbsp;day&nbsp;and&nbsp;hour.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;This&nbsp;routine&nbsp;valid&nbsp;for&nbsp;any&nbsp;'jd'&nbsp;greater&nbsp;than&nbsp;zero.<br>
..&nbsp;[N2]&nbsp;Input&nbsp;Julian&nbsp;date&nbsp;can&nbsp;be&nbsp;based&nbsp;on&nbsp;any&nbsp;UT-like&nbsp;time&nbsp;scale<br>
&nbsp;&nbsp;&nbsp;&nbsp;(UTC,&nbsp;UT1,&nbsp;TT,&nbsp;etc.)&nbsp;--&nbsp;output&nbsp;time&nbsp;value&nbsp;will&nbsp;have&nbsp;same&nbsp;basis.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Fliegel,&nbsp;H.&nbsp;&amp;&nbsp;Van&nbsp;Flandern,&nbsp;T.&nbsp;Comm.&nbsp;of&nbsp;the&nbsp;ACM,&nbsp;Vol.&nbsp;11,<br>
&nbsp;&nbsp;&nbsp;&nbsp;No.&nbsp;10,&nbsp;October&nbsp;1968,&nbsp;p.&nbsp;657.</tt></dd></dl>
 <dl><dt><a name="-cel2ter"><strong>cel2ter</strong></a>(jd_ut1_high, jd_ut1_low, delta_t, xp, yp, vec1, method<font color="#909090">=0</font>, option<font color="#909090">=0</font>, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Rotates&nbsp;a&nbsp;vector&nbsp;from&nbsp;the&nbsp;celestial&nbsp;to&nbsp;the&nbsp;terrestrial&nbsp;system.<br>
Specifically,&nbsp;transforms&nbsp;a&nbsp;vector&nbsp;in&nbsp;the&nbsp;GCRS&nbsp;(a&nbsp;local&nbsp;space-fixed<br>
system)&nbsp;to&nbsp;the&nbsp;ITRS&nbsp;(a&nbsp;rotating&nbsp;earth-fixed&nbsp;system)&nbsp;by&nbsp;applying<br>
rotations&nbsp;for&nbsp;the&nbsp;GCRS-to-dynamical&nbsp;frame&nbsp;tie,&nbsp;precession,&nbsp;nutation,<br>
Earth&nbsp;rotation,&nbsp;and&nbsp;polar&nbsp;motion.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_ut1_high&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;High-order&nbsp;part&nbsp;of&nbsp;UT1&nbsp;Julian&nbsp;date.<br>
jd_ut1_low&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Low-order&nbsp;part&nbsp;of&nbsp;UT1&nbsp;Julian&nbsp;date.<br>
delta_t&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Value&nbsp;of&nbsp;Delta&nbsp;T&nbsp;(=&nbsp;TT&nbsp;-&nbsp;UT1)&nbsp;at&nbsp;the&nbsp;input&nbsp;UT1&nbsp;Julian&nbsp;date.<br>
xp&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Conventionally-defined&nbsp;X&nbsp;coordinate&nbsp;of&nbsp;celestial&nbsp;intermediate<br>
&nbsp;&nbsp;&nbsp;&nbsp;pole&nbsp;with&nbsp;respect&nbsp;to&nbsp;ITRS&nbsp;pole,&nbsp;in&nbsp;arcseconds.<br>
yp&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Conventionally-defined&nbsp;Y&nbsp;coordinate&nbsp;of&nbsp;celestial&nbsp;intermediate<br>
&nbsp;&nbsp;&nbsp;&nbsp;pole&nbsp;with&nbsp;respect&nbsp;to&nbsp;ITRS&nbsp;pole,&nbsp;in&nbsp;arcseconds.<br>
vec1&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;geocentric&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates,<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;GCRS&nbsp;axes&nbsp;(celestial&nbsp;system)&nbsp;or&nbsp;with&nbsp;respect&nbsp;to&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date,&nbsp;depending&nbsp;on&nbsp;'option'.<br>
method&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Selection&nbsp;for&nbsp;method<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;CIO-based&nbsp;method&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;equinox-based&nbsp;method<br>
option&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Selection&nbsp;for&nbsp;reference&nbsp;axes<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;The&nbsp;output&nbsp;vector&nbsp;is&nbsp;referred&nbsp;to&nbsp;GCRS&nbsp;axes.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;The&nbsp;output&nbsp;vector&nbsp;is&nbsp;produced&nbsp;with&nbsp;respect&nbsp;to&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date.&nbsp;See&nbsp;Note&nbsp;2&nbsp;below.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
vec2&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;geocentric&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates,<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;ITRS&nbsp;axes&nbsp;(terrestrial&nbsp;system)&nbsp;in&nbsp;the&nbsp;normal&nbsp;case<br>
&nbsp;&nbsp;&nbsp;&nbsp;where&nbsp;'option'&nbsp;=&nbsp;0.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;'xp'&nbsp;=&nbsp;'yp'&nbsp;=&nbsp;0&nbsp;means&nbsp;no&nbsp;polar&nbsp;motion&nbsp;transformation.<br>
..&nbsp;[N2]&nbsp;The&nbsp;'option'&nbsp;flag&nbsp;only&nbsp;works&nbsp;for&nbsp;the&nbsp;equinox-based&nbsp;method.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C54.<br>
..&nbsp;[R2]&nbsp;Kaplan,&nbsp;G.&nbsp;H.&nbsp;(2003),&nbsp;'Another&nbsp;Look&nbsp;at&nbsp;Non-Rotating<br>
&nbsp;&nbsp;&nbsp;&nbsp;Origins',&nbsp;Proceedings&nbsp;of&nbsp;IAU&nbsp;XXV&nbsp;Joint&nbsp;Discussion&nbsp;16.</tt></dd></dl>
 <dl><dt><a name="-cel_pole"><strong>cel_pole</strong></a>(tjd, type, dpole1, dpole2)</dt><dd><tt>This&nbsp;function&nbsp;allows&nbsp;for&nbsp;the&nbsp;specification&nbsp;of&nbsp;celestial&nbsp;pole<br>
offsets&nbsp;for&nbsp;high-precision&nbsp;applications.&nbsp;Each&nbsp;set&nbsp;of&nbsp;offsets&nbsp;is<br>
a&nbsp;correction&nbsp;to&nbsp;the&nbsp;modeled&nbsp;position&nbsp;of&nbsp;the&nbsp;pole&nbsp;for&nbsp;a&nbsp;specific<br>
date,&nbsp;derived&nbsp;from&nbsp;observations&nbsp;and&nbsp;published&nbsp;by&nbsp;the&nbsp;IERS.<br>
&nbsp;<br>
Parameters<br>
----------<br>
tjd&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TDB&nbsp;or&nbsp;TT&nbsp;Julian&nbsp;day&nbsp;for&nbsp;pole&nbsp;offsets.<br>
type&nbsp;:&nbsp;{1,&nbsp;2}<br>
&nbsp;&nbsp;&nbsp;&nbsp;Type&nbsp;of&nbsp;pole&nbsp;offset.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;for&nbsp;corrections&nbsp;to&nbsp;angular&nbsp;coordinates&nbsp;of&nbsp;modeled&nbsp;pole<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;mean&nbsp;ecliptic&nbsp;of&nbsp;date,&nbsp;that&nbsp;is,<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;delta-delta-psi&nbsp;and&nbsp;delta-delta-epsilon.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;2&nbsp;for&nbsp;corrections&nbsp;to&nbsp;components&nbsp;of&nbsp;modeled&nbsp;pole&nbsp;unit<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;vector&nbsp;referred&nbsp;to&nbsp;GCRS&nbsp;axes,&nbsp;that&nbsp;is,&nbsp;dx&nbsp;and&nbsp;dy.<br>
dpole1&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Value&nbsp;of&nbsp;celestial&nbsp;pole&nbsp;offset&nbsp;in&nbsp;first&nbsp;coordinate,<br>
&nbsp;&nbsp;&nbsp;&nbsp;(delta-delta-psi&nbsp;or&nbsp;dx)&nbsp;in&nbsp;milliarcseconds.<br>
dpole2&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Value&nbsp;of&nbsp;celestial&nbsp;pole&nbsp;offset&nbsp;in&nbsp;second&nbsp;coordinate,<br>
&nbsp;&nbsp;&nbsp;&nbsp;(delta-delta-epsilon&nbsp;or&nbsp;dy)&nbsp;in&nbsp;milliarcseconds.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;This&nbsp;function&nbsp;sets&nbsp;the&nbsp;values&nbsp;of&nbsp;global&nbsp;variables&nbsp;'PSI_COR'<br>
&nbsp;&nbsp;&nbsp;&nbsp;and&nbsp;'EPS_COR'&nbsp;declared&nbsp;at&nbsp;the&nbsp;top&nbsp;of&nbsp;file&nbsp;'novas.c'.&nbsp;These<br>
&nbsp;&nbsp;&nbsp;&nbsp;global&nbsp;variables&nbsp;are&nbsp;used&nbsp;only&nbsp;in&nbsp;NOVAS&nbsp;function&nbsp;'e_tilt'.<br>
..&nbsp;[N2]&nbsp;This&nbsp;function,&nbsp;if&nbsp;used,&nbsp;should&nbsp;be&nbsp;called&nbsp;before&nbsp;any&nbsp;other<br>
&nbsp;&nbsp;&nbsp;&nbsp;NOVAS&nbsp;functions&nbsp;for&nbsp;a&nbsp;given&nbsp;date.&nbsp;Values&nbsp;of&nbsp;the&nbsp;pole&nbsp;offsets<br>
&nbsp;&nbsp;&nbsp;&nbsp;specified&nbsp;via&nbsp;a&nbsp;call&nbsp;to&nbsp;this&nbsp;function&nbsp;will&nbsp;be&nbsp;used&nbsp;until<br>
&nbsp;&nbsp;&nbsp;&nbsp;explicitly&nbsp;changed.<br>
..&nbsp;[N3]&nbsp;'tjd'&nbsp;is&nbsp;used&nbsp;only&nbsp;for&nbsp;'type'&nbsp;=&nbsp;2,&nbsp;to&nbsp;transform&nbsp;dx&nbsp;and&nbsp;dy&nbsp;to<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;equivalent&nbsp;delta-delta-psi&nbsp;and&nbsp;delta-delta-epsilon&nbsp;values.<br>
..&nbsp;[N4]&nbsp;For&nbsp;'type'&nbsp;=&nbsp;2,&nbsp;dx&nbsp;and&nbsp;dy&nbsp;are&nbsp;unit&nbsp;vector&nbsp;component<br>
&nbsp;&nbsp;&nbsp;&nbsp;corrections,&nbsp;but&nbsp;are&nbsp;expressed&nbsp;in&nbsp;milliarcseconds&nbsp;simply&nbsp;by<br>
&nbsp;&nbsp;&nbsp;&nbsp;multiplying&nbsp;by&nbsp;206264806,&nbsp;the&nbsp;number&nbsp;of&nbsp;milliarcseconds&nbsp;in&nbsp;one<br>
&nbsp;&nbsp;&nbsp;&nbsp;radian.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Kaplan,&nbsp;G.&nbsp;(2005),&nbsp;US&nbsp;Naval&nbsp;Observatory&nbsp;Circular&nbsp;179.<br>
..&nbsp;[R2]&nbsp;Kaplan,&nbsp;G.&nbsp;(2003),&nbsp;USNO/AA&nbsp;Technical&nbsp;Note&nbsp;2003-03.</tt></dd></dl>
 <dl><dt><a name="-cio_basis"><strong>cio_basis</strong></a>(jd_tdb, ra_cio, system, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Compute&nbsp;the&nbsp;orthonormal&nbsp;basis&nbsp;vectors,&nbsp;with&nbsp;respect&nbsp;to&nbsp;the&nbsp;GCRS<br>
(geocentric&nbsp;ICRS),&nbsp;of&nbsp;the&nbsp;celestial&nbsp;intermediate&nbsp;system&nbsp;defined&nbsp;by<br>
the&nbsp;celestial&nbsp;intermediate&nbsp;pole&nbsp;(CIP)&nbsp;(in&nbsp;the&nbsp;z&nbsp;direction)&nbsp;and&nbsp;the<br>
celestial&nbsp;intermediate&nbsp;origin&nbsp;(CIO)&nbsp;(in&nbsp;the&nbsp;x&nbsp;direction).&nbsp;A&nbsp;TDB<br>
Julian&nbsp;date&nbsp;and&nbsp;the&nbsp;right&nbsp;ascension&nbsp;of&nbsp;the&nbsp;CIO&nbsp;at&nbsp;that&nbsp;date&nbsp;is<br>
required&nbsp;as&nbsp;input.&nbsp;The&nbsp;right&nbsp;ascension&nbsp;of&nbsp;the&nbsp;CIO&nbsp;can&nbsp;be&nbsp;with<br>
respect&nbsp;to&nbsp;either&nbsp;the&nbsp;GCRS&nbsp;origin&nbsp;or&nbsp;the&nbsp;true&nbsp;equinox&nbsp;of&nbsp;date&nbsp;--<br>
different&nbsp;algorithms&nbsp;are&nbsp;used&nbsp;in&nbsp;the&nbsp;two&nbsp;cases.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tdb&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TDB&nbsp;Julian&nbsp;date&nbsp;of&nbsp;epoch.<br>
ra_cio&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Right&nbsp;ascension&nbsp;of&nbsp;the&nbsp;CIO&nbsp;at&nbsp;epoch&nbsp;in&nbsp;hours.<br>
system&nbsp;:&nbsp;{1,&nbsp;2},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Reference&nbsp;system&nbsp;in&nbsp;which&nbsp;right&nbsp;ascension&nbsp;is&nbsp;given&nbsp;(output<br>
&nbsp;&nbsp;&nbsp;&nbsp;from&nbsp;function&nbsp;'cio_location')<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;GCRS<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;2&nbsp;...&nbsp;True&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(x,&nbsp;y,&nbsp;z)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Unit&nbsp;vector&nbsp;toward&nbsp;(the&nbsp;CIO,&nbsp;the&nbsp;y-direction,&nbsp;north&nbsp;celestial<br>
&nbsp;&nbsp;&nbsp;&nbsp;pole&nbsp;(CIP)),&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates,&nbsp;referred&nbsp;to<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;GCRS<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;This&nbsp;function&nbsp;effectively&nbsp;constructs&nbsp;the&nbsp;matrix&nbsp;C&nbsp;in&nbsp;eq.&nbsp;(3)<br>
&nbsp;&nbsp;&nbsp;&nbsp;of&nbsp;the&nbsp;reference.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Kaplan,&nbsp;G.&nbsp;(2005),&nbsp;US&nbsp;Naval&nbsp;Observatory&nbsp;Circular&nbsp;179.</tt></dd></dl>
 <dl><dt><a name="-cio_location"><strong>cio_location</strong></a>(jd_tdb, accuracy<font color="#909090">=0</font>)</dt></dl>
 <dl><dt><a name="-cio_ra"><strong>cio_ra</strong></a>(jd_tt, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Returns&nbsp;the&nbsp;true&nbsp;right&nbsp;ascension&nbsp;of&nbsp;the&nbsp;celestial&nbsp;intermediate<br>
origin&nbsp;(CIO)&nbsp;at&nbsp;a&nbsp;given&nbsp;TT&nbsp;Julian&nbsp;date.&nbsp;This&nbsp;is&nbsp;-(equation&nbsp;of&nbsp;the<br>
origins).<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;day.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
ra_cio&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Right&nbsp;ascension&nbsp;of&nbsp;the&nbsp;CIO,&nbsp;with&nbsp;respect&nbsp;to&nbsp;the&nbsp;true&nbsp;equinox<br>
&nbsp;&nbsp;&nbsp;&nbsp;of&nbsp;date,&nbsp;in&nbsp;hours&nbsp;(+&nbsp;or&nbsp;-).<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Kaplan,&nbsp;G.&nbsp;(2005),&nbsp;US&nbsp;Naval&nbsp;Observatory&nbsp;Circular&nbsp;179.</tt></dd></dl>
 <dl><dt><a name="-d_light"><strong>d_light</strong></a>(pos_star, pos_obs)</dt><dd><tt>Computes&nbsp;the&nbsp;difference&nbsp;in&nbsp;light-time,&nbsp;for&nbsp;a&nbsp;star,&nbsp;between&nbsp;the<br>
barycenter&nbsp;of&nbsp;the&nbsp;solar&nbsp;system&nbsp;and&nbsp;the&nbsp;observer&nbsp;(or&nbsp;the&nbsp;geocenter).<br>
&nbsp;<br>
Parameters<br>
----------<br>
pos_star&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;of&nbsp;star,&nbsp;with&nbsp;respect&nbsp;to&nbsp;origin&nbsp;at&nbsp;solar&nbsp;system<br>
&nbsp;&nbsp;&nbsp;&nbsp;barycenter.<br>
pos_obs&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;of&nbsp;observer&nbsp;(or&nbsp;the&nbsp;geocenter),&nbsp;with&nbsp;respect<br>
&nbsp;&nbsp;&nbsp;&nbsp;to&nbsp;origin&nbsp;at&nbsp;solar&nbsp;system&nbsp;barycenter,&nbsp;components&nbsp;in&nbsp;AU.<br>
&nbsp;<br>
Returns<br>
-------<br>
diflt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Difference&nbsp;in&nbsp;light&nbsp;time,&nbsp;in&nbsp;the&nbsp;sense&nbsp;star&nbsp;to&nbsp;barycenter&nbsp;minus<br>
&nbsp;&nbsp;&nbsp;&nbsp;star&nbsp;to&nbsp;earth,&nbsp;in&nbsp;days.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;Alternatively,&nbsp;this&nbsp;function&nbsp;returns&nbsp;the&nbsp;light-time&nbsp;from&nbsp;the<br>
observer&nbsp;(or&nbsp;the&nbsp;geocenter)&nbsp;to&nbsp;a&nbsp;point&nbsp;on&nbsp;a&nbsp;light&nbsp;ray&nbsp;that&nbsp;is<br>
closest&nbsp;to&nbsp;a&nbsp;specific&nbsp;solar&nbsp;system&nbsp;body.&nbsp;For&nbsp;this&nbsp;purpose,&nbsp;'pos1'<br>
is&nbsp;the&nbsp;position&nbsp;vector&nbsp;toward&nbsp;observed&nbsp;object,&nbsp;with&nbsp;respect&nbsp;to<br>
origin&nbsp;at&nbsp;observer&nbsp;(or&nbsp;the&nbsp;geocenter);&nbsp;'pos_obs'&nbsp;is&nbsp;the&nbsp;position<br>
vector&nbsp;of&nbsp;solar&nbsp;system&nbsp;body,&nbsp;with&nbsp;respect&nbsp;to&nbsp;origin&nbsp;at&nbsp;observer<br>
(or&nbsp;the&nbsp;geocenter),&nbsp;components&nbsp;in&nbsp;AU;&nbsp;and&nbsp;the&nbsp;returned&nbsp;value&nbsp;is<br>
the&nbsp;light&nbsp;time&nbsp;to&nbsp;point&nbsp;on&nbsp;line&nbsp;defined&nbsp;by&nbsp;'pos1'&nbsp;that&nbsp;is&nbsp;closest<br>
to&nbsp;solar&nbsp;system&nbsp;body&nbsp;(positive&nbsp;if&nbsp;light&nbsp;passes&nbsp;body&nbsp;before&nbsp;hitting<br>
observer,&nbsp;i.e.,&nbsp;if&nbsp;'pos1'&nbsp;is&nbsp;within&nbsp;90&nbsp;degrees&nbsp;of&nbsp;'pos_obs').</tt></dd></dl>
 <dl><dt><a name="-e_tilt"><strong>e_tilt</strong></a>(jd_tdb, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Computes&nbsp;quantities&nbsp;related&nbsp;to&nbsp;the&nbsp;orientation&nbsp;of&nbsp;the&nbsp;Earth's<br>
rotation&nbsp;axis&nbsp;at&nbsp;the&nbsp;given&nbsp;Julian&nbsp;day.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tdb&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TDB&nbsp;Julian&nbsp;date.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;quantities.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(mobl,&nbsp;tobl,&nbsp;ee,&nbsp;dpsi,&nbsp;deps)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;five&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;mobl&nbsp;=&nbsp;mean&nbsp;obliquity&nbsp;of&nbsp;the&nbsp;ecliptic&nbsp;in&nbsp;degrees.<br>
&nbsp;&nbsp;&nbsp;&nbsp;tobl&nbsp;=&nbsp;true&nbsp;obliquity&nbsp;of&nbsp;the&nbsp;ecliptic&nbsp;in&nbsp;degrees.<br>
&nbsp;&nbsp;&nbsp;&nbsp;ee&nbsp;&nbsp;&nbsp;=&nbsp;equation&nbsp;of&nbsp;the&nbsp;equinoxes&nbsp;in&nbsp;seconds&nbsp;of&nbsp;time.<br>
&nbsp;&nbsp;&nbsp;&nbsp;dpsi&nbsp;=&nbsp;nutation&nbsp;in&nbsp;longitude&nbsp;in&nbsp;arcseconds.<br>
&nbsp;&nbsp;&nbsp;&nbsp;deps&nbsp;=&nbsp;nutation&nbsp;in&nbsp;obliquity&nbsp;in&nbsp;arcseconds.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;Values&nbsp;of&nbsp;the&nbsp;celestial&nbsp;pole&nbsp;offsets&nbsp;'PSI_COR'&nbsp;and&nbsp;'EPS_COR'<br>
&nbsp;&nbsp;&nbsp;&nbsp;are&nbsp;set&nbsp;using&nbsp;function&nbsp;'cel_pole',&nbsp;if&nbsp;desired.&nbsp;See&nbsp;the&nbsp;docstring<br>
&nbsp;&nbsp;&nbsp;&nbsp;for&nbsp;'cel_pole'&nbsp;for&nbsp;details.</tt></dd></dl>
 <dl><dt><a name="-ecl2equ_vec"><strong>ecl2equ_vec</strong></a>(jd_tt, position, coord_sys<font color="#909090">=2</font>, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Converts&nbsp;an&nbsp;ecliptic&nbsp;position&nbsp;vector&nbsp;to&nbsp;an&nbsp;equatorial&nbsp;position<br>
vector.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date&nbsp;of&nbsp;equator,&nbsp;equinox,&nbsp;and&nbsp;ecliptic&nbsp;used&nbsp;for<br>
&nbsp;&nbsp;&nbsp;&nbsp;coordinates.<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;referred&nbsp;to&nbsp;specified&nbsp;ecliptic&nbsp;and&nbsp;equinox&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;date.&nbsp;If&nbsp;'system'&nbsp;=&nbsp;2,&nbsp;'position'&nbsp;must&nbsp;be&nbsp;on&nbsp;mean&nbsp;ecliptic&nbsp;and<br>
&nbsp;&nbsp;&nbsp;&nbsp;equinox&nbsp;of&nbsp;J2000.0;&nbsp;see&nbsp;Note&nbsp;[N1]_&nbsp;below.<br>
coord_sys&nbsp;:&nbsp;{0,&nbsp;1,&nbsp;2},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;mean&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;true&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;2&nbsp;...&nbsp;ICRS&nbsp;(ecliptic&nbsp;is&nbsp;always&nbsp;the&nbsp;mean&nbsp;plane)&nbsp;(default)<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
position2&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;referred&nbsp;to&nbsp;specified&nbsp;ecliptic&nbsp;and&nbsp;equinox&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;date.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;To&nbsp;convert&nbsp;an&nbsp;ecliptic&nbsp;vector&nbsp;(mean&nbsp;ecliptic&nbsp;and&nbsp;equinox&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;J2000.0&nbsp;only)&nbsp;to&nbsp;an&nbsp;ICRS&nbsp;vector,&nbsp;set&nbsp;'system'&nbsp;=&nbsp;2;&nbsp;the&nbsp;value<br>
&nbsp;&nbsp;&nbsp;&nbsp;of&nbsp;'jd_tt'&nbsp;can&nbsp;be&nbsp;set&nbsp;to&nbsp;anything,&nbsp;since&nbsp;J2000.0&nbsp;is&nbsp;assumed.<br>
&nbsp;&nbsp;&nbsp;&nbsp;Except&nbsp;for&nbsp;the&nbsp;output&nbsp;from&nbsp;this&nbsp;case,&nbsp;all&nbsp;vectors&nbsp;are&nbsp;assumed&nbsp;to<br>
&nbsp;&nbsp;&nbsp;&nbsp;be&nbsp;with&nbsp;respect&nbsp;to&nbsp;a&nbsp;dynamical&nbsp;system.</tt></dd></dl>
 <dl><dt><a name="-ee_ct"><strong>ee_ct</strong></a>(jd_tt_high, jd_tt_low, accuracy<font color="#909090">=0</font>)</dt><dd><tt>To&nbsp;compute&nbsp;the&nbsp;"complementary&nbsp;terms"&nbsp;of&nbsp;the&nbsp;equation&nbsp;of&nbsp;the<br>
equinoxes.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt_high&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;High-order&nbsp;(integer)&nbsp;part&nbsp;of&nbsp;TT&nbsp;Julian&nbsp;day.<br>
jd_tt_low&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Low-order&nbsp;(fractional)&nbsp;part&nbsp;of&nbsp;TT&nbsp;Julian&nbsp;day.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;terms.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
comp_terms&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Complementary&nbsp;terms,&nbsp;in&nbsp;radians.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;The&nbsp;series&nbsp;used&nbsp;in&nbsp;this&nbsp;function&nbsp;was&nbsp;derived&nbsp;from&nbsp;the&nbsp;first<br>
&nbsp;&nbsp;&nbsp;&nbsp;reference.&nbsp;&nbsp;This&nbsp;same&nbsp;series&nbsp;was&nbsp;also&nbsp;adopted&nbsp;for&nbsp;use&nbsp;in&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;IAU's&nbsp;Standards&nbsp;of&nbsp;Fundamental&nbsp;Astronomy&nbsp;(SOFA)&nbsp;software&nbsp;(i.e.,<br>
&nbsp;&nbsp;&nbsp;&nbsp;subroutine&nbsp;eect00.for&nbsp;and&nbsp;function&nbsp;eect00.c).<br>
..&nbsp;[N2]&nbsp;The&nbsp;low-accuracy&nbsp;series&nbsp;used&nbsp;in&nbsp;this&nbsp;function&nbsp;is&nbsp;a&nbsp;simple<br>
&nbsp;&nbsp;&nbsp;&nbsp;implementation&nbsp;derived&nbsp;from&nbsp;the&nbsp;first&nbsp;reference,&nbsp;in&nbsp;which&nbsp;terms<br>
&nbsp;&nbsp;&nbsp;&nbsp;smaller&nbsp;than&nbsp;2&nbsp;microarcseconds&nbsp;have&nbsp;been&nbsp;omitted.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Capitaine,&nbsp;N.,&nbsp;Wallace,&nbsp;P.T.,&nbsp;and&nbsp;McCarthy,&nbsp;D.D.&nbsp;(2003).<br>
&nbsp;&nbsp;&nbsp;&nbsp;Astron.&nbsp;&amp;&nbsp;Astrophys.&nbsp;406,&nbsp;p.&nbsp;1135-1149.&nbsp;Table&nbsp;3.<br>
..&nbsp;[R2]&nbsp;IERS&nbsp;Conventions&nbsp;(2010),&nbsp;Chapter&nbsp;5,&nbsp;p.&nbsp;60,&nbsp;Table&nbsp;5.2e.<br>
&nbsp;&nbsp;&nbsp;&nbsp;(Table&nbsp;5.2e&nbsp;presented&nbsp;in&nbsp;the&nbsp;printed&nbsp;publication&nbsp;is&nbsp;a&nbsp;truncated<br>
&nbsp;&nbsp;&nbsp;&nbsp;series.&nbsp;The&nbsp;full&nbsp;series,&nbsp;which&nbsp;is&nbsp;used&nbsp;in&nbsp;NOVAS,&nbsp;is&nbsp;available<br>
&nbsp;&nbsp;&nbsp;&nbsp;on&nbsp;the&nbsp;IERS&nbsp;Conventions&nbsp;Center&nbsp;website&nbsp;in&nbsp;file&nbsp;tab5.2e.txt.)<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="ftp://tai.bipm.org/iers/conv2010/chapter5/">ftp://tai.bipm.org/iers/conv2010/chapter5/</a></tt></dd></dl>
 <dl><dt><a name="-ephemeris"><strong>ephemeris</strong></a>(jd, ss_body, origin<font color="#909090">=1</font>, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Retrieves&nbsp;the&nbsp;position&nbsp;and&nbsp;velocity&nbsp;of&nbsp;a&nbsp;solar&nbsp;system&nbsp;body&nbsp;from<br>
a&nbsp;fundamental&nbsp;ephemeris.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;2<br>
&nbsp;&nbsp;&nbsp;&nbsp;TDB&nbsp;Julian&nbsp;date&nbsp;split&nbsp;into&nbsp;two&nbsp;parts,&nbsp;where&nbsp;the&nbsp;sum&nbsp;jd[0]&nbsp;+<br>
&nbsp;&nbsp;&nbsp;&nbsp;jd[1]&nbsp;is&nbsp;the&nbsp;TDB&nbsp;Julian&nbsp;date.<br>
ss_body&nbsp;:&nbsp;<a href="#Object">Object</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#Object">Object</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;the&nbsp;designation&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;body&nbsp;of&nbsp;interest.<br>
origin&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;solar&nbsp;system&nbsp;barycenter<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;center&nbsp;of&nbsp;mass&nbsp;of&nbsp;the&nbsp;Sun&nbsp;(default)<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position&nbsp;and<br>
&nbsp;&nbsp;&nbsp;&nbsp;velocity.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(pos,&nbsp;vel)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;tuples&nbsp;of&nbsp;three&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;pos&nbsp;is&nbsp;position&nbsp;vector&nbsp;of&nbsp;the&nbsp;body&nbsp;at&nbsp;'jd_tdb';&nbsp;equatorial<br>
&nbsp;&nbsp;&nbsp;&nbsp;rectangular&nbsp;coordinates&nbsp;in&nbsp;AU&nbsp;referred&nbsp;to&nbsp;the&nbsp;ICRS.<br>
&nbsp;&nbsp;&nbsp;&nbsp;vel&nbsp;is&nbsp;the&nbsp;velocity&nbsp;vector&nbsp;of&nbsp;the&nbsp;body&nbsp;at&nbsp;'jd_tdb';&nbsp;equatorial<br>
&nbsp;&nbsp;&nbsp;&nbsp;rectangular&nbsp;system&nbsp;referred&nbsp;the&nbsp;ICRS,&nbsp;in&nbsp;AU/Day.</tt></dd></dl>
 <dl><dt><a name="-equ2ecl"><strong>equ2ecl</strong></a>(jd_tt, ra, dec, coord_sys<font color="#909090">=2</font>, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Convert&nbsp;equatorial&nbsp;position&nbsp;to&nbsp;ecliptic&nbsp;position<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date&nbsp;of&nbsp;equator,&nbsp;equinox,&nbsp;and&nbsp;ecliptic&nbsp;used&nbsp;for<br>
&nbsp;&nbsp;&nbsp;&nbsp;coordinates.<br>
ra&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Right&nbsp;ascension&nbsp;in&nbsp;hours,&nbsp;referred&nbsp;to&nbsp;specified&nbsp;equator&nbsp;and<br>
&nbsp;&nbsp;&nbsp;&nbsp;equinox&nbsp;of&nbsp;date.<br>
dec&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Declination&nbsp;in&nbsp;degrees,&nbsp;referred&nbsp;to&nbsp;specified&nbsp;equator&nbsp;and<br>
&nbsp;&nbsp;&nbsp;&nbsp;equinox&nbsp;of&nbsp;date.<br>
coord_sys&nbsp;:&nbsp;{0,&nbsp;1,&nbsp;2},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;mean&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;true&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;2&nbsp;...&nbsp;ICRS&nbsp;(ecliptic&nbsp;is&nbsp;always&nbsp;the&nbsp;mean&nbsp;plane)&nbsp;(default)<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(elon,&nbsp;elat)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Ecliptic&nbsp;(longitude,&nbsp;latitude)&nbsp;in&nbsp;degrees,&nbsp;referred&nbsp;to&nbsp;specified<br>
&nbsp;&nbsp;&nbsp;&nbsp;ecliptic&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;To&nbsp;convert&nbsp;ICRS&nbsp;RA&nbsp;and&nbsp;dec&nbsp;to&nbsp;ecliptic&nbsp;coordinates&nbsp;(mean<br>
&nbsp;&nbsp;&nbsp;&nbsp;ecliptic&nbsp;and&nbsp;equinox&nbsp;of&nbsp;J2000.0),&nbsp;set&nbsp;'system'&nbsp;=&nbsp;2;&nbsp;the&nbsp;value<br>
&nbsp;&nbsp;&nbsp;&nbsp;of&nbsp;'jd_tt'&nbsp;can&nbsp;be&nbsp;set&nbsp;to&nbsp;anything,&nbsp;since&nbsp;J2000.0&nbsp;is&nbsp;assumed.<br>
&nbsp;&nbsp;&nbsp;&nbsp;Except&nbsp;for&nbsp;the&nbsp;input&nbsp;to&nbsp;this&nbsp;case,&nbsp;all&nbsp;input&nbsp;coordinates&nbsp;are<br>
&nbsp;&nbsp;&nbsp;&nbsp;dynamical.</tt></dd></dl>
 <dl><dt><a name="-equ2ecl_vec"><strong>equ2ecl_vec</strong></a>(jd_tt, position, coord_sys<font color="#909090">=2</font>, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Convert&nbsp;an&nbsp;equatorial&nbsp;position&nbsp;vector&nbsp;to&nbsp;an&nbsp;ecliptic&nbsp;position<br>
vector.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date&nbsp;of&nbsp;equator,&nbsp;equinox,&nbsp;and&nbsp;ecliptic&nbsp;used&nbsp;for<br>
&nbsp;&nbsp;&nbsp;&nbsp;coordinates.<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;referred&nbsp;to&nbsp;specified&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;date.<br>
coord_sys&nbsp;:&nbsp;{0,&nbsp;1,&nbsp;2},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;mean&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;true&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;2&nbsp;...&nbsp;ICRS&nbsp;(ecliptic&nbsp;is&nbsp;always&nbsp;the&nbsp;mean&nbsp;plane)&nbsp;(default)<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;referred&nbsp;to&nbsp;specified&nbsp;ecliptic&nbsp;and&nbsp;equinox&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;date.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;To&nbsp;convert&nbsp;an&nbsp;ICRS&nbsp;vector&nbsp;to&nbsp;an&nbsp;ecliptic&nbsp;vector&nbsp;(mean<br>
&nbsp;&nbsp;&nbsp;&nbsp;ecliptic&nbsp;and&nbsp;equinox&nbsp;of&nbsp;J2000.0&nbsp;only),&nbsp;set&nbsp;'system'&nbsp;=&nbsp;2;&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;value&nbsp;of&nbsp;'jd_tt'&nbsp;can&nbsp;be&nbsp;set&nbsp;to&nbsp;anything,&nbsp;since&nbsp;J2000.0&nbsp;is<br>
&nbsp;&nbsp;&nbsp;&nbsp;assumed.&nbsp;Except&nbsp;for&nbsp;the&nbsp;input&nbsp;to&nbsp;this&nbsp;case,&nbsp;all&nbsp;vectors&nbsp;are<br>
&nbsp;&nbsp;&nbsp;&nbsp;assumed&nbsp;to&nbsp;be&nbsp;with&nbsp;respect&nbsp;to&nbsp;a&nbsp;dynamical&nbsp;system.</tt></dd></dl>
 <dl><dt><a name="-equ2gal"><strong>equ2gal</strong></a>(rai, deci)</dt><dd><tt>Convert&nbsp;ICRS&nbsp;equatorial&nbsp;position&nbsp;to&nbsp;galactic&nbsp;position<br>
&nbsp;<br>
Parameters<br>
----------<br>
ra&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;ICRS&nbsp;right&nbsp;ascension&nbsp;in&nbsp;hours.<br>
dec&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;ICRS&nbsp;declination&nbsp;in&nbsp;degrees.<br>
&nbsp;<br>
Returns<br>
-------<br>
(glon,&nbsp;glat)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Galactic&nbsp;(longitude,&nbsp;latitude)&nbsp;in&nbsp;degrees.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Hipparcos&nbsp;and&nbsp;Tycho&nbsp;Catalogues,&nbsp;Vol.&nbsp;1,&nbsp;Section&nbsp;1.5.3.</tt></dd></dl>
 <dl><dt><a name="-equ2hor"><strong>equ2hor</strong></a>(jd_ut1, delta_t, xp, yp, location, ra, dec, ref_option<font color="#909090">=0</font>, accuracy<font color="#909090">=0</font>)</dt><dd><tt>This&nbsp;function&nbsp;transforms&nbsp;topocentric&nbsp;right&nbsp;ascension&nbsp;and&nbsp;declination<br>
to&nbsp;zenith&nbsp;distance&nbsp;and&nbsp;azimuth.&nbsp;It&nbsp;uses&nbsp;a&nbsp;method&nbsp;that&nbsp;properly<br>
accounts&nbsp;for&nbsp;polar&nbsp;motion,&nbsp;which&nbsp;is&nbsp;significant&nbsp;at&nbsp;the&nbsp;sub-arcsecond<br>
level.&nbsp;This&nbsp;function&nbsp;can&nbsp;also&nbsp;adjust&nbsp;coordinates&nbsp;for&nbsp;atmospheric<br>
refraction.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_ut1&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;UT1&nbsp;Julian&nbsp;date.<br>
delta_t&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Difference&nbsp;TT-UT1&nbsp;at&nbsp;'jd_ut1',&nbsp;in&nbsp;seconds.<br>
xp&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Conventionally-defined&nbsp;x&nbsp;coordinate&nbsp;of&nbsp;celestial&nbsp;intermediate<br>
&nbsp;&nbsp;&nbsp;&nbsp;pole&nbsp;with&nbsp;respect&nbsp;to&nbsp;ITRS&nbsp;reference&nbsp;pole,&nbsp;in&nbsp;arcseconds.<br>
yp&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Conventionally-defined&nbsp;y&nbsp;coordinate&nbsp;of&nbsp;celestial&nbsp;intermediate<br>
&nbsp;&nbsp;&nbsp;&nbsp;pole&nbsp;with&nbsp;respect&nbsp;to&nbsp;ITRS&nbsp;reference&nbsp;pole,&nbsp;in&nbsp;arcseconds.<br>
location&nbsp;:&nbsp;<a href="#OnSurface">OnSurface</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#OnSurface">OnSurface</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;observer's<br>
&nbsp;&nbsp;&nbsp;&nbsp;location.<br>
ra&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Topocentric&nbsp;right&nbsp;ascension&nbsp;of&nbsp;object&nbsp;of&nbsp;interest,&nbsp;in&nbsp;hours,<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;true&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date.<br>
dec&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Topocentric&nbsp;declination&nbsp;of&nbsp;object&nbsp;of&nbsp;interest,&nbsp;in&nbsp;hours,<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;true&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date.<br>
ref_option&nbsp;:&nbsp;{0,&nbsp;1,&nbsp;2},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;no&nbsp;refraction&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;include&nbsp;refraction,&nbsp;using&nbsp;'standard'&nbsp;atmospheric<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;conditions.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;2&nbsp;...&nbsp;include&nbsp;refraction,&nbsp;using&nbsp;atmospheric&nbsp;parameters<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;input&nbsp;in&nbsp;the&nbsp;'location'&nbsp;object.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(zd,&nbsp;az)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Topocentric&nbsp;(zenith&nbsp;distance,&nbsp;azimuth)&nbsp;in&nbsp;degrees.&nbsp;Zenith<br>
&nbsp;&nbsp;&nbsp;&nbsp;distance&nbsp;is&nbsp;affected&nbsp;by&nbsp;refraction&nbsp;if&nbsp;'ref_option',&nbsp;is&nbsp;non-zero.<br>
&nbsp;&nbsp;&nbsp;&nbsp;Azimuth&nbsp;is&nbsp;measured&nbsp;east&nbsp;from&nbsp;north.<br>
(rar,&nbsp;decr)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Topocentric&nbsp;(right&nbsp;ascension&nbsp;in&nbsp;hours,&nbsp;declination&nbsp;in&nbsp;degrees)<br>
&nbsp;&nbsp;&nbsp;&nbsp;of&nbsp;object&nbsp;of&nbsp;interest,&nbsp;referred&nbsp;to&nbsp;true&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;date,&nbsp;affected&nbsp;by&nbsp;refraction&nbsp;if&nbsp;'ref_option'&nbsp;is&nbsp;non-zero.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;'xp'&nbsp;and&nbsp;'yp'&nbsp;can&nbsp;be&nbsp;set&nbsp;to&nbsp;zero&nbsp;if&nbsp;sub-arcsecond&nbsp;accuracy<br>
&nbsp;&nbsp;&nbsp;&nbsp;is&nbsp;not&nbsp;needed.&nbsp;'ra'&nbsp;and&nbsp;'dec'&nbsp;can&nbsp;be&nbsp;obtained&nbsp;from&nbsp;functions<br>
&nbsp;&nbsp;&nbsp;&nbsp;'topo_star'&nbsp;or&nbsp;'topo_planet'.<br>
..&nbsp;[N2]&nbsp;The&nbsp;directions&nbsp;'zd'=&nbsp;0&nbsp;(zenith)&nbsp;and&nbsp;'az'=&nbsp;0&nbsp;(North)&nbsp;are&nbsp;here<br>
&nbsp;&nbsp;&nbsp;&nbsp;considered&nbsp;fixed&nbsp;in&nbsp;the&nbsp;terrestrial&nbsp;system.&nbsp;Specifically,&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;zenith&nbsp;is&nbsp;along&nbsp;the&nbsp;geodetic&nbsp;normal,&nbsp;and&nbsp;North&nbsp;is&nbsp;toward<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;ITRS&nbsp;pole.<br>
..&nbsp;[N3]&nbsp;If&nbsp;'ref_option'=&nbsp;0,&nbsp;then&nbsp;'rar'='ra'&nbsp;and&nbsp;'decr'='dec'.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Kaplan,&nbsp;G.&nbsp;(2008).&nbsp;USNO/AA&nbsp;Technical&nbsp;Note&nbsp;of&nbsp;28&nbsp;Apr&nbsp;2008,<br>
&nbsp;&nbsp;&nbsp;&nbsp;"Refraction&nbsp;as&nbsp;a&nbsp;Vector."</tt></dd></dl>
 <dl><dt><a name="-era"><strong>era</strong></a>(jd_ut1_high, jd_ut1_low<font color="#909090">=0.0</font>)</dt><dd><tt>Compute&nbsp;the&nbsp;Earth&nbsp;Rotation&nbsp;Angle&nbsp;(theta)&nbsp;for&nbsp;a&nbsp;given&nbsp;UT1&nbsp;Julian<br>
date.&nbsp;The&nbsp;expression&nbsp;used&nbsp;is&nbsp;taken&nbsp;from&nbsp;the&nbsp;note&nbsp;to&nbsp;IAU&nbsp;Resolution<br>
B1.8&nbsp;of&nbsp;2000[R1]_.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_ut1_high&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;High-order&nbsp;part&nbsp;of&nbsp;UT1&nbsp;Julian&nbsp;date.<br>
jd_ut1_low&nbsp;:&nbsp;float&nbsp;(optional)<br>
&nbsp;&nbsp;&nbsp;&nbsp;Low-order&nbsp;part&nbsp;of&nbsp;UT1&nbsp;Julian&nbsp;date.<br>
&nbsp;<br>
Returns<br>
-------<br>
theta&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;The&nbsp;Earth&nbsp;Rotation&nbsp;Angle&nbsp;in&nbsp;degrees.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;The&nbsp;algorithm&nbsp;used&nbsp;here&nbsp;is&nbsp;equivalent&nbsp;to&nbsp;the&nbsp;canonical<br>
&nbsp;&nbsp;&nbsp;&nbsp;theta&nbsp;=&nbsp;0.7790572732640&nbsp;+&nbsp;1.00273781191135448&nbsp;*&nbsp;t,<br>
&nbsp;&nbsp;&nbsp;&nbsp;where&nbsp;t&nbsp;is&nbsp;the&nbsp;time&nbsp;in&nbsp;days&nbsp;from&nbsp;J2000&nbsp;(t&nbsp;=&nbsp;jd_ut1_high&nbsp;+<br>
&nbsp;&nbsp;&nbsp;&nbsp;jd_ut1_low&nbsp;-&nbsp;T0),&nbsp;but&nbsp;it&nbsp;avoids&nbsp;many&nbsp;two-PI&nbsp;'wraps'&nbsp;that<br>
&nbsp;&nbsp;&nbsp;&nbsp;decrease&nbsp;precision&nbsp;(adopted&nbsp;from&nbsp;SOFA&nbsp;Fortran&nbsp;routine&nbsp;iau_era00;<br>
&nbsp;&nbsp;&nbsp;&nbsp;see&nbsp;also&nbsp;expression&nbsp;at&nbsp;top&nbsp;of&nbsp;page&nbsp;35&nbsp;of&nbsp;IERS&nbsp;Conventions<br>
&nbsp;&nbsp;&nbsp;&nbsp;(1996)).<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;IAU&nbsp;Resolution&nbsp;B1.8,&nbsp;adopted&nbsp;at&nbsp;the&nbsp;2000&nbsp;IAU&nbsp;General<br>
&nbsp;&nbsp;&nbsp;&nbsp;Assembly,&nbsp;Manchester,&nbsp;UK.<br>
..&nbsp;[R2]&nbsp;Kaplan,&nbsp;G.&nbsp;(2005),&nbsp;US&nbsp;Naval&nbsp;Observatory&nbsp;Circular&nbsp;179.</tt></dd></dl>
 <dl><dt><a name="-frame_tie"><strong>frame_tie</strong></a>(position, direction<font color="#909090">=0</font>)</dt><dd><tt>Transform&nbsp;a&nbsp;vector&nbsp;from&nbsp;the&nbsp;dynamical&nbsp;reference&nbsp;system&nbsp;to&nbsp;the<br>
International&nbsp;Celestial&nbsp;Reference&nbsp;System&nbsp;(ICRS),&nbsp;or&nbsp;vice&nbsp;versa.&nbsp;The<br>
dynamical&nbsp;reference&nbsp;system&nbsp;is&nbsp;based&nbsp;on&nbsp;the&nbsp;dynamical&nbsp;mean&nbsp;equator<br>
and&nbsp;equinox&nbsp;of&nbsp;J2000.0.&nbsp;The&nbsp;ICRS&nbsp;is&nbsp;based&nbsp;on&nbsp;the&nbsp;space-fixed&nbsp;ICRS<br>
axes&nbsp;defined&nbsp;by&nbsp;the&nbsp;radio&nbsp;catalog&nbsp;positions&nbsp;of&nbsp;several&nbsp;hundred<br>
extragalactic&nbsp;objects.<br>
&nbsp;<br>
Parameters<br>
----------<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;in&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates.<br>
direction&nbsp;:&nbsp;{0,&nbsp;-1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;ICRS&nbsp;to&nbsp;dynamical&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;-1&nbsp;...&nbsp;dynamical&nbsp;to&nbsp;ICRS<br>
&nbsp;<br>
Returns<br>
-------<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;in&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;For&nbsp;geocentric&nbsp;coordinates,&nbsp;the&nbsp;same&nbsp;transformation&nbsp;is&nbsp;used<br>
&nbsp;&nbsp;&nbsp;&nbsp;between&nbsp;the&nbsp;dynamical&nbsp;reference&nbsp;system&nbsp;and&nbsp;the&nbsp;GCRS.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Hilton,&nbsp;J.&nbsp;and&nbsp;Hohenkerk,&nbsp;C.&nbsp;(2004),&nbsp;Astronomy&nbsp;and<br>
&nbsp;&nbsp;&nbsp;&nbsp;Astrophysics&nbsp;413,&nbsp;765-770,&nbsp;eq.&nbsp;(6)&nbsp;and&nbsp;(8).<br>
..&nbsp;[R2]&nbsp;IERS&nbsp;(2003)&nbsp;Conventions,&nbsp;Chapter&nbsp;5.</tt></dd></dl>
 <dl><dt><a name="-fund_args"><strong>fund_args</strong></a>(time)</dt><dd><tt>To&nbsp;compute&nbsp;the&nbsp;fundamental&nbsp;arguments&nbsp;(mean&nbsp;elements)&nbsp;of&nbsp;the&nbsp;Sun&nbsp;and<br>
Moon.<br>
&nbsp;<br>
Parameters<br>
----------<br>
time&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TDB&nbsp;time&nbsp;in&nbsp;Julian&nbsp;centuries&nbsp;since&nbsp;J2000.0<br>
&nbsp;<br>
Returns<br>
-------<br>
(l,&nbsp;l',&nbsp;F,&nbsp;D,&nbsp;omega)&nbsp;:&nbsp;tuple<br>
&nbsp;&nbsp;&nbsp;&nbsp;l&nbsp;=&nbsp;mean&nbsp;anomaly&nbsp;of&nbsp;the&nbsp;Moon<br>
&nbsp;&nbsp;&nbsp;&nbsp;l'&nbsp;=&nbsp;mean&nbsp;anomaly&nbsp;of&nbsp;the&nbsp;Sun<br>
&nbsp;&nbsp;&nbsp;&nbsp;F&nbsp;=&nbsp;mean&nbsp;argument&nbsp;of&nbsp;the&nbsp;latitude&nbsp;of&nbsp;the&nbsp;Moon<br>
&nbsp;&nbsp;&nbsp;&nbsp;D&nbsp;=&nbsp;mean&nbsp;elongation&nbsp;of&nbsp;the&nbsp;Moon&nbsp;from&nbsp;the&nbsp;Sun<br>
&nbsp;&nbsp;&nbsp;&nbsp;omega&nbsp;=&nbsp;mean&nbsp;longitude&nbsp;of&nbsp;the&nbsp;Moon's&nbsp;ascending&nbsp;node;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;from&nbsp;Simon&nbsp;section&nbsp;3.4(b.3),<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;precession&nbsp;=&nbsp;5028.8200&nbsp;arcsec/cy<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Simon&nbsp;et&nbsp;al.&nbsp;(1994)&nbsp;Astronomy&nbsp;and&nbsp;Astrophysics&nbsp;282,&nbsp;663-683,<br>
&nbsp;&nbsp;&nbsp;&nbsp;esp.&nbsp;Sections&nbsp;3.4-3.5.</tt></dd></dl>
 <dl><dt><a name="-gcrs2equ"><strong>gcrs2equ</strong></a>(jd_tt, rag, decg, coord_sys<font color="#909090">=1</font>, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Convert&nbsp;GCRS&nbsp;right&nbsp;ascension&nbsp;and&nbsp;declination&nbsp;to&nbsp;coordinates&nbsp;with<br>
respect&nbsp;to&nbsp;the&nbsp;equator&nbsp;of&nbsp;date&nbsp;(mean&nbsp;or&nbsp;true).&nbsp;For&nbsp;coordinates&nbsp;with<br>
respect&nbsp;to&nbsp;the&nbsp;true&nbsp;equator&nbsp;of&nbsp;date,&nbsp;the&nbsp;origin&nbsp;of&nbsp;right&nbsp;ascension<br>
can&nbsp;be&nbsp;either&nbsp;the&nbsp;true&nbsp;equinox&nbsp;or&nbsp;the&nbsp;celestial&nbsp;intermediate&nbsp;origin<br>
(CIO).<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date&nbsp;of&nbsp;equator&nbsp;to&nbsp;be&nbsp;used&nbsp;for&nbsp;output&nbsp;coordinates.<br>
rag&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;GCRS&nbsp;right&nbsp;ascension&nbsp;in&nbsp;hours.<br>
decg&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;GCRS&nbsp;declination&nbsp;in&nbsp;degrees.<br>
coord_sys&nbsp;:&nbsp;{0,&nbsp;1,&nbsp;2},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;mean&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;true&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;2&nbsp;...&nbsp;true&nbsp;equator&nbsp;and&nbsp;CIO&nbsp;of&nbsp;date<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(ra,&nbsp;dec)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;(Right&nbsp;ascension&nbsp;in&nbsp;hours,&nbsp;declination&nbsp;in&nbsp;degrees),&nbsp;referred&nbsp;to<br>
&nbsp;&nbsp;&nbsp;&nbsp;specified&nbsp;equator&nbsp;(and&nbsp;right&nbsp;ascension&nbsp;origin,&nbsp;for&nbsp;'ra')&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;date.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;Set&nbsp;input&nbsp;value&nbsp;of&nbsp;'accuracy'&nbsp;equal&nbsp;to&nbsp;any&nbsp;short&nbsp;int&nbsp;if<br>
&nbsp;&nbsp;&nbsp;&nbsp;'coord_sys'&nbsp;equals&nbsp;0&nbsp;or&nbsp;1.&nbsp;It&nbsp;is&nbsp;not&nbsp;used&nbsp;in&nbsp;these&nbsp;cases.<br>
..&nbsp;[N2]&nbsp;This&nbsp;function&nbsp;only&nbsp;supports&nbsp;the&nbsp;CIO-based&nbsp;method.</tt></dd></dl>
 <dl><dt><a name="-geo_posvel"><strong>geo_posvel</strong></a>(jd_tt, delta_t, observer, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Compute&nbsp;the&nbsp;geocentric&nbsp;position&nbsp;and&nbsp;velocity&nbsp;of&nbsp;an&nbsp;observer&nbsp;on&nbsp;the<br>
surface&nbsp;of&nbsp;the&nbsp;earth&nbsp;or&nbsp;on&nbsp;a&nbsp;near-earth&nbsp;spacecraft.&nbsp;The&nbsp;final<br>
vectors&nbsp;are&nbsp;expressed&nbsp;in&nbsp;the&nbsp;GCRS.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date.<br>
delta_t&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Value&nbsp;of&nbsp;Delta&nbsp;T&nbsp;(=TT-UT1)&nbsp;at&nbsp;'date'.<br>
observer&nbsp;:&nbsp;<a href="#Observer">Observer</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#Observer">Observer</a>&nbsp;type&nbsp;object&nbsp;specifying&nbsp;the&nbsp;location&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;observer.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position&nbsp;and<br>
&nbsp;&nbsp;&nbsp;&nbsp;velocity.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(position,&nbsp;velocity)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;of&nbsp;observer,&nbsp;with&nbsp;respect&nbsp;to&nbsp;origin&nbsp;at<br>
&nbsp;&nbsp;&nbsp;&nbsp;geocenter,&nbsp;referred&nbsp;to&nbsp;GCRS&nbsp;axes,&nbsp;components&nbsp;in&nbsp;AU&nbsp;and&nbsp;AU/day,<br>
&nbsp;&nbsp;&nbsp;&nbsp;respectively.</tt></dd></dl>
 <dl><dt><a name="-get_errno"><strong>get_errno</strong></a>(...)</dt></dl>
 <dl><dt><a name="-grav_def"><strong>grav_def</strong></a>(jd_tdb, pos_obj, pos_obs, location, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Compute&nbsp;the&nbsp;total&nbsp;gravitational&nbsp;deflection&nbsp;of&nbsp;light&nbsp;for&nbsp;the&nbsp;observed<br>
object&nbsp;due&nbsp;to&nbsp;the&nbsp;major&nbsp;gravitating&nbsp;bodies&nbsp;in&nbsp;the&nbsp;solar&nbsp;system.&nbsp;This<br>
function&nbsp;valid&nbsp;for&nbsp;an&nbsp;observed&nbsp;body&nbsp;within&nbsp;the&nbsp;solar&nbsp;system&nbsp;as&nbsp;well<br>
as&nbsp;for&nbsp;a&nbsp;star.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tdb&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TDB&nbsp;Julian&nbsp;date&nbsp;of&nbsp;observation.<br>
pos_obj&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;of&nbsp;observed&nbsp;object,&nbsp;with&nbsp;respect&nbsp;to&nbsp;origin&nbsp;at<br>
&nbsp;&nbsp;&nbsp;&nbsp;observer&nbsp;(or&nbsp;the&nbsp;geocenter),&nbsp;referred&nbsp;to&nbsp;ICRS&nbsp;axes,&nbsp;components<br>
&nbsp;&nbsp;&nbsp;&nbsp;in&nbsp;AU.<br>
pos_obs&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;of&nbsp;observer&nbsp;(or&nbsp;the&nbsp;geocenter),&nbsp;with&nbsp;respect&nbsp;to<br>
&nbsp;&nbsp;&nbsp;&nbsp;origin&nbsp;at&nbsp;solar&nbsp;system&nbsp;barycenter,&nbsp;referred&nbsp;to&nbsp;ICRS&nbsp;axes,<br>
&nbsp;&nbsp;&nbsp;&nbsp;components&nbsp;in&nbsp;AU.<br>
location&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;for&nbsp;location&nbsp;of&nbsp;observer,&nbsp;determining&nbsp;whether&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;gravitational&nbsp;deflection&nbsp;due&nbsp;to&nbsp;the&nbsp;earth&nbsp;itself&nbsp;is&nbsp;applied.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;No&nbsp;earth&nbsp;deflection&nbsp;(normally&nbsp;means&nbsp;observer&nbsp;is&nbsp;at<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;geocenter)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;Add&nbsp;in&nbsp;earth&nbsp;deflection&nbsp;(normally&nbsp;means&nbsp;observer&nbsp;is<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;on&nbsp;or&nbsp;above&nbsp;surface&nbsp;of&nbsp;earth,&nbsp;including&nbsp;earth&nbsp;orbit)<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
positon&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;of&nbsp;observed&nbsp;object,&nbsp;with&nbsp;respect&nbsp;to&nbsp;origin&nbsp;at<br>
&nbsp;&nbsp;&nbsp;&nbsp;observer&nbsp;(or&nbsp;the&nbsp;geocenter),&nbsp;referred&nbsp;to&nbsp;ICRS&nbsp;axes,&nbsp;corrected<br>
&nbsp;&nbsp;&nbsp;&nbsp;for&nbsp;gravitational&nbsp;deflection,&nbsp;components&nbsp;in&nbsp;AU.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;If&nbsp;'accuracy'&nbsp;is&nbsp;set&nbsp;to&nbsp;zero&nbsp;(full&nbsp;accuracy),&nbsp;three&nbsp;bodies<br>
(Sun,&nbsp;Jupiter,&nbsp;and&nbsp;Saturn)&nbsp;are&nbsp;used&nbsp;in&nbsp;the&nbsp;calculation.&nbsp;If<br>
the&nbsp;reduced-accuracy&nbsp;option&nbsp;is&nbsp;set,&nbsp;only&nbsp;the&nbsp;Sun&nbsp;is&nbsp;used&nbsp;in&nbsp;the<br>
calculation.&nbsp;In&nbsp;both&nbsp;cases,&nbsp;if&nbsp;the&nbsp;observer&nbsp;is&nbsp;not&nbsp;at&nbsp;the<br>
geocenter,&nbsp;the&nbsp;deflection&nbsp;due&nbsp;to&nbsp;the&nbsp;Earth&nbsp;is&nbsp;included.<br>
..&nbsp;[N2]&nbsp;The&nbsp;number&nbsp;of&nbsp;bodies&nbsp;used&nbsp;at&nbsp;full&nbsp;and&nbsp;reduced&nbsp;accuracy&nbsp;can<br>
be&nbsp;set&nbsp;by&nbsp;making&nbsp;a&nbsp;change&nbsp;to&nbsp;the&nbsp;code&nbsp;in&nbsp;this&nbsp;function&nbsp;as&nbsp;indicated<br>
in&nbsp;the&nbsp;comments.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Klioner,&nbsp;S.&nbsp;(2003),&nbsp;Astronomical&nbsp;Journal&nbsp;125,&nbsp;1580-1597,<br>
&nbsp;&nbsp;&nbsp;&nbsp;Section&nbsp;6.</tt></dd></dl>
 <dl><dt><a name="-grav_vec"><strong>grav_vec</strong></a>(pos_obj, pos_obs, pos_body, rmass)</dt><dd><tt>Correct&nbsp;the&nbsp;position&nbsp;vector&nbsp;for&nbsp;the&nbsp;deflection&nbsp;of&nbsp;light&nbsp;in&nbsp;the<br>
gravitational&nbsp;field&nbsp;of&nbsp;an&nbsp;arbitrary&nbsp;body.&nbsp;This&nbsp;function&nbsp;valid&nbsp;for&nbsp;an<br>
observed&nbsp;body&nbsp;within&nbsp;the&nbsp;solar&nbsp;system&nbsp;as&nbsp;well&nbsp;as&nbsp;for&nbsp;a&nbsp;star.<br>
&nbsp;<br>
Parameters<br>
----------<br>
pos_obj&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;of&nbsp;observed&nbsp;object,&nbsp;with&nbsp;respect&nbsp;to&nbsp;origin&nbsp;at<br>
&nbsp;&nbsp;&nbsp;&nbsp;observer&nbsp;(or&nbsp;the&nbsp;geocenter),&nbsp;components&nbsp;in&nbsp;AU.<br>
pos_obs&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;of&nbsp;observer&nbsp;(or&nbsp;the&nbsp;geocenter),&nbsp;with&nbsp;respect<br>
&nbsp;&nbsp;&nbsp;&nbsp;to&nbsp;origin&nbsp;at&nbsp;solar&nbsp;system&nbsp;barycenter,&nbsp;components&nbsp;in&nbsp;AU.<br>
pos_body&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;of&nbsp;gravitating&nbsp;body,&nbsp;with&nbsp;respect&nbsp;to&nbsp;origin<br>
&nbsp;&nbsp;&nbsp;&nbsp;at&nbsp;solar&nbsp;system&nbsp;barycenter,&nbsp;components&nbsp;in&nbsp;AU.<br>
rmass&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Reciprocal&nbsp;mass&nbsp;of&nbsp;gravitating&nbsp;body&nbsp;in&nbsp;solar&nbsp;mass&nbsp;units,<br>
&nbsp;&nbsp;&nbsp;&nbsp;that&nbsp;is,&nbsp;Sun&nbsp;mass&nbsp;/&nbsp;body&nbsp;mass.<br>
&nbsp;<br>
Returns<br>
-------<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;of&nbsp;observed&nbsp;object,&nbsp;with&nbsp;respect&nbsp;to&nbsp;origin&nbsp;at<br>
&nbsp;&nbsp;&nbsp;&nbsp;observer&nbsp;(or&nbsp;the&nbsp;geocenter),&nbsp;corrected&nbsp;for&nbsp;gravitational<br>
&nbsp;&nbsp;&nbsp;&nbsp;deflection,&nbsp;components&nbsp;in&nbsp;AU.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Murray,&nbsp;C.A.&nbsp;(1981)&nbsp;Mon.&nbsp;Notices&nbsp;Royal&nbsp;Ast.&nbsp;Society&nbsp;195,<br>
&nbsp;&nbsp;&nbsp;&nbsp;639-648.<br>
..&nbsp;[R2]&nbsp;See&nbsp;also&nbsp;formulae&nbsp;in&nbsp;Section&nbsp;B&nbsp;of&nbsp;the&nbsp;Astronomical&nbsp;Almanac,<br>
&nbsp;&nbsp;&nbsp;&nbsp;or&nbsp;Kaplan,&nbsp;G.&nbsp;et&nbsp;al.&nbsp;(1989)&nbsp;Astronomical&nbsp;Journal&nbsp;97,&nbsp;1197-1210,<br>
&nbsp;&nbsp;&nbsp;&nbsp;section&nbsp;iii&nbsp;f.</tt></dd></dl>
 <dl><dt><a name="-ira_equinox"><strong>ira_equinox</strong></a>(jd_tdb, equinox, accuracy<font color="#909090">=0</font>)</dt><dd><tt>To&nbsp;compute&nbsp;the&nbsp;intermediate&nbsp;right&nbsp;ascension&nbsp;of&nbsp;the&nbsp;equinox&nbsp;at<br>
the&nbsp;input&nbsp;Julian&nbsp;date,&nbsp;using&nbsp;an&nbsp;analytical&nbsp;expression&nbsp;for&nbsp;the<br>
accumulated&nbsp;precession&nbsp;in&nbsp;right&nbsp;ascension.&nbsp;For&nbsp;the&nbsp;true&nbsp;equinox,<br>
the&nbsp;result&nbsp;is&nbsp;the&nbsp;equation&nbsp;of&nbsp;the&nbsp;origins.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tdb&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TDB&nbsp;Julian&nbsp;day.<br>
equinox&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;mean&nbsp;equinox<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;true&nbsp;equinox<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
ira_eq&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Intermediate&nbsp;right&nbsp;ascension&nbsp;of&nbsp;the&nbsp;equinox,&nbsp;in&nbsp;hours&nbsp;(+&nbsp;or&nbsp;-).<br>
&nbsp;&nbsp;&nbsp;&nbsp;If&nbsp;'equinox'&nbsp;=&nbsp;1&nbsp;(i.e.&nbsp;true&nbsp;equinox),&nbsp;then&nbsp;the&nbsp;returned&nbsp;value&nbsp;is<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;equation&nbsp;of&nbsp;the&nbsp;origins.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Capitaine,&nbsp;N.&nbsp;et&nbsp;al.&nbsp;(2003),&nbsp;Astronomy&nbsp;and&nbsp;Astrophysics&nbsp;412,<br>
&nbsp;&nbsp;&nbsp;&nbsp;567-586,&nbsp;eq.&nbsp;(42).</tt></dd></dl>
 <dl><dt><a name="-julian_date"><strong>julian_date</strong></a>(year, month, day, hour<font color="#909090">=0.0</font>)</dt><dd><tt>This&nbsp;function&nbsp;will&nbsp;compute&nbsp;the&nbsp;Julian&nbsp;date&nbsp;for&nbsp;a&nbsp;given&nbsp;calendar<br>
date&nbsp;(year,&nbsp;month,&nbsp;day,&nbsp;hour).<br>
&nbsp;<br>
Parameters<br>
----------<br>
year&nbsp;:&nbsp;integer<br>
&nbsp;&nbsp;&nbsp;&nbsp;Year.<br>
month&nbsp;:&nbsp;integer<br>
&nbsp;&nbsp;&nbsp;&nbsp;Month&nbsp;number.<br>
day&nbsp;:&nbsp;integer<br>
&nbsp;&nbsp;&nbsp;&nbsp;Day-of-month.<br>
hour&nbsp;:&nbsp;float,&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Hour-of-day.<br>
&nbsp;<br>
Returns<br>
-------<br>
jd&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Julian&nbsp;day.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;This&nbsp;function&nbsp;makes&nbsp;no&nbsp;checks&nbsp;for&nbsp;a&nbsp;valid&nbsp;input&nbsp;calendar<br>
&nbsp;&nbsp;&nbsp;&nbsp;date.<br>
..&nbsp;[N2]&nbsp;Input&nbsp;calendar&nbsp;date&nbsp;must&nbsp;be&nbsp;Gregorian.<br>
..&nbsp;[N3]&nbsp;Input&nbsp;time&nbsp;value&nbsp;can&nbsp;be&nbsp;based&nbsp;on&nbsp;any&nbsp;UT-like&nbsp;time&nbsp;scale<br>
&nbsp;&nbsp;&nbsp;&nbsp;(UTC,&nbsp;UT1,&nbsp;TT,&nbsp;etc.)&nbsp;--&nbsp;output&nbsp;Julian&nbsp;date&nbsp;will&nbsp;have&nbsp;the&nbsp;same<br>
&nbsp;&nbsp;&nbsp;&nbsp;basis.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Fliegel,&nbsp;H.&nbsp;&amp;&nbsp;Van&nbsp;Flandern,&nbsp;T.&nbsp;Comm.&nbsp;of&nbsp;the&nbsp;ACM,&nbsp;Vol.&nbsp;11,<br>
&nbsp;&nbsp;&nbsp;&nbsp;No.&nbsp;10,&nbsp;October&nbsp;1968,&nbsp;p.&nbsp;657.</tt></dd></dl>
 <dl><dt><a name="-light_time"><strong>light_time</strong></a>(jd_tdb, ss_object, pos_obs, estimate<font color="#909090">=0.0</font>, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Compute&nbsp;the&nbsp;geocentric&nbsp;position&nbsp;of&nbsp;a&nbsp;solar&nbsp;system&nbsp;body,&nbsp;as&nbsp;antedated<br>
for&nbsp;light-time.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tdb&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TDB&nbsp;Julian&nbsp;date&nbsp;of&nbsp;observation.<br>
ss_object&nbsp;:&nbsp;<a href="#Object">Object</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#Object">Object</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;the&nbsp;designation&nbsp;for<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;solar&nbsp;system&nbsp;body.<br>
pos_obs&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;of&nbsp;observer&nbsp;(or&nbsp;the&nbsp;geocenter),&nbsp;with&nbsp;respect&nbsp;to<br>
&nbsp;&nbsp;&nbsp;&nbsp;origin&nbsp;at&nbsp;solar&nbsp;system&nbsp;barycenter,&nbsp;referred&nbsp;to&nbsp;ICRS&nbsp;axes,<br>
&nbsp;&nbsp;&nbsp;&nbsp;components&nbsp;in&nbsp;AU.<br>
estimate&nbsp;:&nbsp;float&nbsp;(optional)<br>
&nbsp;&nbsp;&nbsp;&nbsp;First&nbsp;approximation&nbsp;to&nbsp;light-time,&nbsp;in&nbsp;days&nbsp;(can&nbsp;be&nbsp;set&nbsp;to&nbsp;0.0<br>
&nbsp;&nbsp;&nbsp;&nbsp;if&nbsp;unknown).<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position&nbsp;and<br>
&nbsp;&nbsp;&nbsp;&nbsp;time.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(position,&nbsp;time)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3,&nbsp;and&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;of&nbsp;body,&nbsp;with&nbsp;respect&nbsp;to&nbsp;origin&nbsp;at&nbsp;observer&nbsp;(or<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;geocenter),&nbsp;referred&nbsp;to&nbsp;ICRS&nbsp;axes,&nbsp;components&nbsp;in&nbsp;AU&nbsp;and<br>
&nbsp;&nbsp;&nbsp;&nbsp;final&nbsp;light-time,&nbsp;in&nbsp;days.</tt></dd></dl>
 <dl><dt><a name="-limb_angle"><strong>limb_angle</strong></a>(pos_obj, pos_obs)</dt><dd><tt>Compute&nbsp;the&nbsp;angle&nbsp;of&nbsp;an&nbsp;object&nbsp;above&nbsp;or&nbsp;below&nbsp;the&nbsp;Earth's&nbsp;limb<br>
(horizon).&nbsp;The&nbsp;geometric&nbsp;limb&nbsp;is&nbsp;computed,&nbsp;assuming&nbsp;the&nbsp;Earth&nbsp;to&nbsp;be<br>
an&nbsp;airless&nbsp;sphere&nbsp;(no&nbsp;refraction&nbsp;or&nbsp;oblateness&nbsp;is&nbsp;included).&nbsp;The<br>
observer&nbsp;can&nbsp;be&nbsp;on&nbsp;or&nbsp;above&nbsp;the&nbsp;Earth.&nbsp;For&nbsp;an&nbsp;observer&nbsp;on&nbsp;the<br>
surface&nbsp;of&nbsp;the&nbsp;Earth,&nbsp;this&nbsp;function&nbsp;returns&nbsp;the&nbsp;approximate<br>
unrefracted&nbsp;altitude.<br>
&nbsp;<br>
Parameters<br>
----------<br>
pos_obj&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;of&nbsp;observed&nbsp;object,&nbsp;with&nbsp;respect&nbsp;to&nbsp;origin&nbsp;at<br>
&nbsp;&nbsp;&nbsp;&nbsp;geocenter,&nbsp;components&nbsp;in&nbsp;AU.<br>
pos_obs&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;of&nbsp;observer,&nbsp;with&nbsp;respect&nbsp;to&nbsp;origin&nbsp;at<br>
&nbsp;&nbsp;&nbsp;&nbsp;geocenter,&nbsp;components&nbsp;in&nbsp;AU.<br>
&nbsp;<br>
Returns<br>
-------<br>
(limb_angle,&nbsp;nadir_angle)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Angle&nbsp;of&nbsp;observed&nbsp;object&nbsp;above&nbsp;(+)&nbsp;or&nbsp;below&nbsp;(-)&nbsp;limb&nbsp;in&nbsp;degrees<br>
&nbsp;&nbsp;&nbsp;&nbsp;and&nbsp;nadir&nbsp;angle&nbsp;of&nbsp;observed&nbsp;object&nbsp;as&nbsp;a&nbsp;fraction&nbsp;of&nbsp;apparent<br>
&nbsp;&nbsp;&nbsp;&nbsp;radius&nbsp;of&nbsp;limb&nbsp;where:&nbsp;&lt;&nbsp;1.0,&nbsp;below&nbsp;the&nbsp;limb;&nbsp;=&nbsp;1.0,&nbsp;on&nbsp;the&nbsp;limb;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&gt;&nbsp;1.0,&nbsp;above&nbsp;the&nbsp;limb</tt></dd></dl>
 <dl><dt><a name="-local_planet"><strong>local_planet</strong></a>(jd_tt, delta_t, ss_body, position, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Computes&nbsp;the&nbsp;local&nbsp;place&nbsp;of&nbsp;a&nbsp;solar&nbsp;system&nbsp;body.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date&nbsp;for&nbsp;local&nbsp;place.<br>
delta_t&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Difference&nbsp;TT-UT1&nbsp;at&nbsp;'date',&nbsp;in&nbsp;seconds&nbsp;of&nbsp;time.<br>
ss_body&nbsp;:&nbsp;<a href="#Object">Object</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#Object">Object</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;the&nbsp;body&nbsp;designation<br>
&nbsp;&nbsp;&nbsp;&nbsp;for&nbsp;solar&nbsp;system&nbsp;body.<br>
position&nbsp;:&nbsp;<a href="#OnSurface">OnSurface</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#OnSurface">OnSurface</a>&nbsp;type&nbsp;object&nbsp;specifying&nbsp;the&nbsp;position&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;observer.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(ra,&nbsp;dec,&nbsp;dis)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Local&nbsp;(right&nbsp;ascension&nbsp;in&nbsp;hours,&nbsp;declination&nbsp;in&nbsp;degrees,&nbsp;...),<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;the&nbsp;'local&nbsp;GCRS',&nbsp;and&nbsp;true&nbsp;(...,&nbsp;...,&nbsp;distance&nbsp;in<br>
&nbsp;&nbsp;&nbsp;&nbsp;AU)&nbsp;from&nbsp;Earth&nbsp;to&nbsp;solar&nbsp;system&nbsp;body&nbsp;at&nbsp;'jd_tt'.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C72-C72.<br>
..&nbsp;[R2]&nbsp;Explanatory&nbsp;Supplement&nbsp;to&nbsp;the&nbsp;Astronomical&nbsp;Almanac&nbsp;(1992),<br>
&nbsp;&nbsp;&nbsp;&nbsp;Chapter&nbsp;3.</tt></dd></dl>
 <dl><dt><a name="-local_star"><strong>local_star</strong></a>(jd_tt, delta_t, star, position, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Computes&nbsp;the&nbsp;local&nbsp;place&nbsp;of&nbsp;a&nbsp;star&nbsp;at&nbsp;date&nbsp;'date',&nbsp;given&nbsp;its<br>
catalog&nbsp;mean&nbsp;place,&nbsp;proper&nbsp;motion,&nbsp;parallax,&nbsp;and&nbsp;radial&nbsp;velocity.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date&nbsp;for&nbsp;local&nbsp;place.<br>
delta_t&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Difference&nbsp;TT-UT1&nbsp;at&nbsp;'date',&nbsp;in&nbsp;seconds&nbsp;of&nbsp;time.<br>
star&nbsp;:&nbsp;<a href="#CatEntry">CatEntry</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#CatEntry">CatEntry</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;catalog&nbsp;data&nbsp;for<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;object&nbsp;in&nbsp;the&nbsp;ICRS.<br>
position&nbsp;:&nbsp;<a href="#OnSurface">OnSurface</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#OnSurface">OnSurface</a>&nbsp;type&nbsp;object&nbsp;specifying&nbsp;the&nbsp;position&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;observer.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(ra,&nbsp;dec)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Local&nbsp;(right&nbsp;ascension&nbsp;in&nbsp;hours,&nbsp;declination&nbsp;in&nbsp;degrees),<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;the&nbsp;'local&nbsp;GCRS'.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C65.<br>
..&nbsp;[R2]&nbsp;Explanatory&nbsp;Supplement&nbsp;to&nbsp;the&nbsp;Astronomical&nbsp;Almanac&nbsp;(1992),<br>
&nbsp;&nbsp;&nbsp;&nbsp;Chapter&nbsp;3.</tt></dd></dl>
 <dl><dt><a name="-make_cat_entry"><strong>make_cat_entry</strong></a>(star_name, catalog, star_num, ra, dec, pm_ra, pm_dec, parallax, rad_vel)</dt><dd><tt>Create&nbsp;an&nbsp;instance&nbsp;of&nbsp;<a href="#CatEntry">CatEntry</a>&nbsp;containing&nbsp;catalog&nbsp;data&nbsp;for&nbsp;a&nbsp;star&nbsp;or<br>
"star-like"&nbsp;object.<br>
&nbsp;<br>
Parameters<br>
----------<br>
star_name&nbsp;:&nbsp;string<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Object">Object</a>&nbsp;name.&nbsp;Max&nbsp;length&nbsp;determined&nbsp;by&nbsp;SIZE_OF_OBJ_NAME&nbsp;defined<br>
&nbsp;&nbsp;&nbsp;&nbsp;in&nbsp;``novas.h``;&nbsp;defaults&nbsp;to&nbsp;50.<br>
catalog&nbsp;:&nbsp;string<br>
&nbsp;&nbsp;&nbsp;&nbsp;Catalog&nbsp;identifier&nbsp;(e.g.&nbsp;HIP&nbsp;=&nbsp;Hipparcos,&nbsp;TY2&nbsp;=&nbsp;Tycho-2).&nbsp;Max<br>
&nbsp;&nbsp;&nbsp;&nbsp;length&nbsp;determined&nbsp;by&nbsp;SIZE_OF_CAT_NAME&nbsp;defined&nbsp;in&nbsp;``novas.h``;<br>
&nbsp;&nbsp;&nbsp;&nbsp;defaults&nbsp;to&nbsp;3.<br>
star_num&nbsp;:&nbsp;integer<br>
&nbsp;&nbsp;&nbsp;&nbsp;<a href="#Object">Object</a>&nbsp;number&nbsp;in&nbsp;the&nbsp;catalog.<br>
ra&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Right&nbsp;ascension&nbsp;of&nbsp;the&nbsp;object&nbsp;(hours).<br>
dec&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Declination&nbsp;of&nbsp;the&nbsp;object&nbsp;(degrees).<br>
pm_ra&nbsp;:&nbsp;float&nbsp;(optional)<br>
&nbsp;&nbsp;&nbsp;&nbsp;Proper&nbsp;motion&nbsp;in&nbsp;right&nbsp;ascension&nbsp;(milliarcseconds/year).<br>
pm_dec&nbsp;:&nbsp;float&nbsp;(optional)<br>
&nbsp;&nbsp;&nbsp;&nbsp;Proper&nbsp;motion&nbsp;in&nbsp;declination&nbsp;(milliarcseconds/year).<br>
parallax&nbsp;:&nbsp;float&nbsp;(optional)<br>
&nbsp;&nbsp;&nbsp;&nbsp;Parallax&nbsp;(milliarcseconds).<br>
rad_vel&nbsp;:&nbsp;float&nbsp;(optional)<br>
&nbsp;&nbsp;&nbsp;&nbsp;Radial&nbsp;velocity&nbsp;(kilometers/second).<br>
&nbsp;<br>
Returns<br>
-------<br>
star&nbsp;:&nbsp;<a href="#CatEntry">CatEntry</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#CatEntry">CatEntry</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;the&nbsp;input&nbsp;data.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;This&nbsp;function&nbsp;is&nbsp;equivalent&nbsp;to&nbsp;calling&nbsp;the&nbsp;object&nbsp;with<br>
&nbsp;&nbsp;&nbsp;&nbsp;arguments,e.g.,&nbsp;<a href="#CatEntry">CatEntry</a>(star_name,&nbsp;catalog,&nbsp;star_num,&nbsp;...);<br>
&nbsp;&nbsp;&nbsp;&nbsp;this&nbsp;function&nbsp;exists&nbsp;for&nbsp;the&nbsp;purpose&nbsp;of&nbsp;direct&nbsp;compatibility<br>
&nbsp;&nbsp;&nbsp;&nbsp;with&nbsp;NOVAS&nbsp;C.</tt></dd></dl>
 <dl><dt><a name="-make_in_space"><strong>make_in_space</strong></a>(position, velocity)</dt><dd><tt>Makes&nbsp;an&nbsp;instance&nbsp;of&nbsp;<a href="#InSpace">InSpace</a>,&nbsp;specifying&nbsp;the&nbsp;position&nbsp;and&nbsp;velocity<br>
of&nbsp;an&nbsp;observer&nbsp;situated&nbsp;on&nbsp;a&nbsp;near-Earth&nbsp;spacecraft.<br>
&nbsp;<br>
Parameters<br>
----------<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Geocentric&nbsp;position&nbsp;vector&nbsp;(x,&nbsp;y,&nbsp;z)&nbsp;in&nbsp;km.<br>
velocity&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Geocentric&nbsp;velocity&nbsp;vector&nbsp;(x_dot,&nbsp;y_dot,&nbsp;z_dot)&nbsp;in&nbsp;km/s.<br>
&nbsp;<br>
Returns<br>
-------<br>
object&nbsp;:&nbsp;<a href="#InSpace">InSpace</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#InSpace">InSpace</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;the&nbsp;position&nbsp;and<br>
&nbsp;&nbsp;&nbsp;&nbsp;velocity&nbsp;of&nbsp;an&nbsp;observer&nbsp;situated&nbsp;on&nbsp;a&nbsp;near-Earth&nbsp;spacecraft.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;Both&nbsp;input&nbsp;vector&nbsp;tuples&nbsp;are&nbsp;with&nbsp;respect&nbsp;to&nbsp;true&nbsp;equator<br>
&nbsp;&nbsp;&nbsp;&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date.<br>
..&nbsp;[N2]&nbsp;This&nbsp;function&nbsp;is&nbsp;equivalent&nbsp;to&nbsp;calling&nbsp;the&nbsp;object&nbsp;with<br>
&nbsp;&nbsp;&nbsp;&nbsp;arguments,&nbsp;e.g.,&nbsp;<a href="#InSpace">InSpace</a>(sc_pos,&nbsp;sc_vel);<br>
&nbsp;&nbsp;&nbsp;&nbsp;this&nbsp;function&nbsp;exists&nbsp;for&nbsp;the&nbsp;purpose&nbsp;of&nbsp;direct&nbsp;compatibility<br>
&nbsp;&nbsp;&nbsp;&nbsp;with&nbsp;NOVAS&nbsp;C.</tt></dd></dl>
 <dl><dt><a name="-make_object"><strong>make_object</strong></a>(type, number, name, star_data)</dt><dd><tt>Makes&nbsp;an&nbsp;instance&nbsp;of&nbsp;<a href="#Object">Object</a>--specifying&nbsp;a&nbsp;celestial&nbsp;object--based&nbsp;on<br>
the&nbsp;input&nbsp;parameters.<br>
&nbsp;<br>
Parameters<br>
----------<br>
type&nbsp;:&nbsp;integer<br>
&nbsp;&nbsp;&nbsp;&nbsp;Type&nbsp;of&nbsp;object<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;major&nbsp;planet,&nbsp;Sun,&nbsp;or&nbsp;Moon<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;minor&nbsp;planet<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;2&nbsp;...&nbsp;object&nbsp;located&nbsp;outside&nbsp;the&nbsp;solar&nbsp;system&nbsp;(i.e.&nbsp;star,<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;galaxy,&nbsp;nebula,&nbsp;etc.)<br>
number&nbsp;:&nbsp;integer<br>
&nbsp;&nbsp;&nbsp;&nbsp;For&nbsp;'type'&nbsp;=&nbsp;0:&nbsp;Mercury&nbsp;=&nbsp;1,&nbsp;...,&nbsp;Pluto&nbsp;=&nbsp;9,&nbsp;Sun&nbsp;=&nbsp;10,&nbsp;Moon&nbsp;=&nbsp;11<br>
&nbsp;&nbsp;&nbsp;&nbsp;For&nbsp;'type'&nbsp;=&nbsp;1:&nbsp;minor&nbsp;planet&nbsp;number<br>
&nbsp;&nbsp;&nbsp;&nbsp;For&nbsp;'type'&nbsp;=&nbsp;2:&nbsp;set&nbsp;to&nbsp;0&nbsp;(zero)<br>
name&nbsp;:&nbsp;string<br>
&nbsp;&nbsp;&nbsp;&nbsp;Name&nbsp;of&nbsp;the&nbsp;object.&nbsp;Max&nbsp;length&nbsp;determined&nbsp;by&nbsp;SIZE_OF_OBJ_NAME<br>
&nbsp;&nbsp;&nbsp;&nbsp;defined&nbsp;in&nbsp;``novas.h``;&nbsp;defaults&nbsp;to&nbsp;50.<br>
star_data&nbsp;:&nbsp;<a href="#CatEntry">CatEntry</a>&nbsp;(or&nbsp;None&nbsp;if&nbsp;'type'&nbsp;=&nbsp;0&nbsp;or&nbsp;'type'&nbsp;=&nbsp;1;&nbsp;see&nbsp;[N1]_)<br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#CatEntry">CatEntry</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;basic&nbsp;astrometric<br>
&nbsp;&nbsp;&nbsp;&nbsp;data&nbsp;for&nbsp;any&nbsp;celestial&nbsp;object&nbsp;located&nbsp;outside&nbsp;the&nbsp;solar&nbsp;system;<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;catalog&nbsp;data&nbsp;for&nbsp;a&nbsp;star.<br>
&nbsp;<br>
Returns<br>
-------<br>
object&nbsp;:&nbsp;<a href="#Object">Object</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#Object">Object</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;the&nbsp;object&nbsp;definition.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;If&nbsp;'type'&nbsp;=&nbsp;0&nbsp;or&nbsp;'type'&nbsp;=&nbsp;1,&nbsp;None&nbsp;may&nbsp;be&nbsp;given&nbsp;for<br>
&nbsp;&nbsp;&nbsp;&nbsp;'star_data';&nbsp;in&nbsp;this&nbsp;case,&nbsp;a&nbsp;dummy&nbsp;star&nbsp;<a href="#CatEntry">CatEntry</a>&nbsp;will&nbsp;be<br>
&nbsp;&nbsp;&nbsp;&nbsp;constructed&nbsp;for&nbsp;'star_data'&nbsp;automatically.<br>
..&nbsp;[N2]&nbsp;This&nbsp;function&nbsp;is&nbsp;equivalent&nbsp;to&nbsp;calling&nbsp;the&nbsp;object&nbsp;with<br>
&nbsp;&nbsp;&nbsp;&nbsp;arguments,&nbsp;e.g.,&nbsp;<a href="#Object">Object</a>(type,&nbsp;number,&nbsp;name,&nbsp;star_data);<br>
&nbsp;&nbsp;&nbsp;&nbsp;this&nbsp;function&nbsp;exists&nbsp;for&nbsp;the&nbsp;purpose&nbsp;of&nbsp;direct&nbsp;compatibility<br>
&nbsp;&nbsp;&nbsp;&nbsp;with&nbsp;NOVAS&nbsp;C.</tt></dd></dl>
 <dl><dt><a name="-make_observer"><strong>make_observer</strong></a>(location, obs_surface, obs_space)</dt><dd><tt>Makes&nbsp;an&nbsp;instance&nbsp;of&nbsp;<a href="#Observer">Observer</a>,&nbsp;specifying&nbsp;the&nbsp;location&nbsp;of&nbsp;the<br>
observer.<br>
&nbsp;<br>
Parameters<br>
----------<br>
location&nbsp;:&nbsp;{0,&nbsp;1,&nbsp;2}<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;observer&nbsp;at&nbsp;geocenter<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;observer&nbsp;on&nbsp;surface&nbsp;of&nbsp;Earth<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;2&nbsp;...&nbsp;observer&nbsp;on&nbsp;near-earth&nbsp;spacecraft<br>
obs_surface&nbsp;:&nbsp;<a href="#OnSurface">OnSurface</a>&nbsp;(or&nbsp;None&nbsp;if&nbsp;'location'&nbsp;!=&nbsp;1;&nbsp;see&nbsp;[N1]_)<br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#OnSurface">OnSurface</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;data&nbsp;for&nbsp;an<br>
&nbsp;&nbsp;&nbsp;&nbsp;observer's&nbsp;location&nbsp;on&nbsp;the&nbsp;surface&nbsp;of&nbsp;the&nbsp;Earth;&nbsp;used&nbsp;when<br>
&nbsp;&nbsp;&nbsp;&nbsp;'location'&nbsp;=&nbsp;1.<br>
obs_space&nbsp;:&nbsp;<a href="#InSpace">InSpace</a>&nbsp;(or&nbsp;None&nbsp;if&nbsp;'location'&nbsp;!=&nbsp;2;&nbsp;see&nbsp;[N1]_)<br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#InSpace">InSpace</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;data&nbsp;for&nbsp;an<br>
&nbsp;&nbsp;&nbsp;&nbsp;observer's&nbsp;location&nbsp;on&nbsp;a&nbsp;near-earth&nbsp;spacecraft;&nbsp;used&nbsp;when<br>
&nbsp;&nbsp;&nbsp;&nbsp;'location'&nbsp;=&nbsp;2.<br>
&nbsp;<br>
Returns<br>
-------<br>
observer&nbsp;:&nbsp;<a href="#Observer">Observer</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#Observer">Observer</a>&nbsp;type&nbsp;object&nbsp;specifying&nbsp;the&nbsp;location&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;observer.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;If&nbsp;'location'&nbsp;=&nbsp;0&nbsp;or&nbsp;'location'&nbsp;=&nbsp;2,&nbsp;None&nbsp;may&nbsp;be&nbsp;given&nbsp;for<br>
&nbsp;&nbsp;&nbsp;&nbsp;'obs_surface';&nbsp;likewise,&nbsp;if&nbsp;'location'&nbsp;=&nbsp;0&nbsp;or&nbsp;'location'&nbsp;=&nbsp;1,<br>
&nbsp;&nbsp;&nbsp;&nbsp;None&nbsp;may&nbsp;be&nbsp;given&nbsp;for&nbsp;'in_space'.&nbsp;This&nbsp;also&nbsp;means&nbsp;that&nbsp;if<br>
&nbsp;&nbsp;&nbsp;&nbsp;'location'&nbsp;=&nbsp;0,&nbsp;None&nbsp;may&nbsp;be&nbsp;given&nbsp;for&nbsp;both&nbsp;'obs_surface'&nbsp;and<br>
&nbsp;&nbsp;&nbsp;&nbsp;'in_space'.<br>
..&nbsp;[N2]&nbsp;This&nbsp;function&nbsp;is&nbsp;equivalent&nbsp;to&nbsp;calling&nbsp;the&nbsp;object&nbsp;with<br>
&nbsp;&nbsp;&nbsp;&nbsp;arguments,&nbsp;e.g.,&nbsp;<a href="#Observer">Observer</a>(obs_surface,&nbsp;in_space,&nbsp;location);<br>
&nbsp;&nbsp;&nbsp;&nbsp;this&nbsp;function&nbsp;exists&nbsp;for&nbsp;the&nbsp;purpose&nbsp;of&nbsp;direct&nbsp;compatibility<br>
&nbsp;&nbsp;&nbsp;&nbsp;with&nbsp;NOVAS&nbsp;C.</tt></dd></dl>
 <dl><dt><a name="-make_observer_at_geocenter"><strong>make_observer_at_geocenter</strong></a>()</dt><dd><tt>Makes&nbsp;an&nbsp;instance&nbsp;of&nbsp;<a href="#Observer">Observer</a>,&nbsp;specifying&nbsp;an&nbsp;observer&nbsp;at&nbsp;the<br>
geocenter.<br>
&nbsp;<br>
Parameters<br>
----------<br>
None<br>
&nbsp;<br>
Returns<br>
-------<br>
observer&nbsp;:&nbsp;<a href="#Observer">Observer</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#Observer">Observer</a>&nbsp;type&nbsp;object&nbsp;specifying&nbsp;the&nbsp;location&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;observer&nbsp;at&nbsp;the&nbsp;geocenter.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;This&nbsp;function&nbsp;is&nbsp;equivalent&nbsp;to&nbsp;calling&nbsp;the&nbsp;object&nbsp;with<br>
&nbsp;&nbsp;&nbsp;&nbsp;arguments,&nbsp;e.g.,&nbsp;<a href="#Observer">Observer</a>(0,&nbsp;None,&nbsp;None);<br>
&nbsp;&nbsp;&nbsp;&nbsp;this&nbsp;function&nbsp;exists&nbsp;for&nbsp;the&nbsp;purpose&nbsp;of&nbsp;direct&nbsp;compatibility<br>
&nbsp;&nbsp;&nbsp;&nbsp;with&nbsp;NOVAS&nbsp;C.</tt></dd></dl>
 <dl><dt><a name="-make_observer_in_space"><strong>make_observer_in_space</strong></a>(position, velocity)</dt><dd><tt>Makes&nbsp;an&nbsp;instance&nbsp;of&nbsp;<a href="#Observer">Observer</a>,&nbsp;specifying&nbsp;the&nbsp;position&nbsp;and&nbsp;velocity<br>
of&nbsp;observer&nbsp;situated&nbsp;on&nbsp;a&nbsp;near-Earth&nbsp;spacecraft.<br>
&nbsp;<br>
Parameters<br>
----------<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Geocentric&nbsp;position&nbsp;vector&nbsp;(x,&nbsp;y,&nbsp;z)&nbsp;in&nbsp;km.<br>
velocity&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Geocentric&nbsp;velocity&nbsp;vector&nbsp;(x_dot,&nbsp;y_dot,&nbsp;z_dot)&nbsp;in&nbsp;km/s.<br>
&nbsp;<br>
Returns<br>
-------<br>
observer&nbsp;:&nbsp;<a href="#Observer">Observer</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#Observer">Observer</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;the&nbsp;position&nbsp;and<br>
&nbsp;&nbsp;&nbsp;&nbsp;velocity&nbsp;of&nbsp;an&nbsp;observer&nbsp;situated&nbsp;on&nbsp;a&nbsp;near-Earth&nbsp;spacecraft.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;Both&nbsp;input&nbsp;vector&nbsp;tuples&nbsp;are&nbsp;with&nbsp;respect&nbsp;to&nbsp;true&nbsp;equator<br>
&nbsp;&nbsp;&nbsp;&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date.<br>
..&nbsp;[N2]&nbsp;This&nbsp;function&nbsp;is&nbsp;equivalent&nbsp;to&nbsp;calling&nbsp;the&nbsp;object&nbsp;with<br>
&nbsp;&nbsp;&nbsp;&nbsp;arguments,&nbsp;e.g.,&nbsp;<a href="#Observer">Observer</a>(2,&nbsp;None,&nbsp;obs_space);<br>
&nbsp;&nbsp;&nbsp;&nbsp;this&nbsp;function&nbsp;exists&nbsp;for&nbsp;the&nbsp;purpose&nbsp;of&nbsp;direct&nbsp;compatibility<br>
&nbsp;&nbsp;&nbsp;&nbsp;with&nbsp;NOVAS&nbsp;C.</tt></dd></dl>
 <dl><dt><a name="-make_observer_on_surface"><strong>make_observer_on_surface</strong></a>(latitude, longitude, height, temperature, pressure)</dt><dd><tt>Makes&nbsp;an&nbsp;instance&nbsp;of&nbsp;<a href="#Observer">Observer</a>,&nbsp;specifying&nbsp;the&nbsp;location&nbsp;of&nbsp;and<br>
weather&nbsp;for&nbsp;an&nbsp;observer&nbsp;on&nbsp;the&nbsp;surface&nbsp;of&nbsp;the&nbsp;Earth.<br>
&nbsp;<br>
Parameters<br>
----------<br>
latitude&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Geodetic&nbsp;(ITRS)&nbsp;latitude&nbsp;in&nbsp;degrees;&nbsp;north&nbsp;positive.<br>
longitude&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Geodetic&nbsp;(ITRS)&nbsp;longitude&nbsp;in&nbsp;degrees;&nbsp;east&nbsp;positive.<br>
height&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Height&nbsp;of&nbsp;the&nbsp;observer&nbsp;(meters).<br>
temperature&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Temperature&nbsp;(degrees&nbsp;Celcius).<br>
pressure&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Atmospheric&nbsp;pressure&nbsp;(millibars).<br>
&nbsp;<br>
Returns<br>
-------<br>
observer&nbsp;:&nbsp;<a href="#Observer">Observer</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#Observer">Observer</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;the&nbsp;location&nbsp;of&nbsp;and<br>
&nbsp;&nbsp;&nbsp;&nbsp;weather&nbsp;for&nbsp;an&nbsp;observer&nbsp;on&nbsp;the&nbsp;surface&nbsp;of&nbsp;the&nbsp;Earth.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;This&nbsp;function&nbsp;is&nbsp;equivalent&nbsp;to&nbsp;calling&nbsp;the&nbsp;object&nbsp;with<br>
&nbsp;&nbsp;&nbsp;&nbsp;arguments,&nbsp;e.g.,&nbsp;<a href="#Observer">Observer</a>(1,&nbsp;obs_surface,&nbsp;None);<br>
&nbsp;&nbsp;&nbsp;&nbsp;this&nbsp;function&nbsp;exists&nbsp;for&nbsp;the&nbsp;purpose&nbsp;of&nbsp;direct&nbsp;compatibility<br>
&nbsp;&nbsp;&nbsp;&nbsp;with&nbsp;NOVAS&nbsp;C.</tt></dd></dl>
 <dl><dt><a name="-make_on_surface"><strong>make_on_surface</strong></a>(latitude, longitude, height, temperature, pressure)</dt><dd><tt>Makes&nbsp;an&nbsp;instance&nbsp;of&nbsp;<a href="#OnSurface">OnSurface</a>,&nbsp;specifying&nbsp;the&nbsp;location&nbsp;of&nbsp;and<br>
weather&nbsp;for&nbsp;an&nbsp;observer&nbsp;on&nbsp;the&nbsp;surface&nbsp;of&nbsp;the&nbsp;Earth.<br>
&nbsp;<br>
Parameters<br>
----------<br>
latitude&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Geodetic&nbsp;(ITRS)&nbsp;latitude&nbsp;in&nbsp;degrees;&nbsp;north&nbsp;positive.<br>
longitude&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Geodetic&nbsp;(ITRS)&nbsp;longitude&nbsp;in&nbsp;degrees;&nbsp;east&nbsp;positive.<br>
height&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Height&nbsp;of&nbsp;the&nbsp;observer&nbsp;(meters).<br>
temperature&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Temperature&nbsp;(degrees&nbsp;Celcius).<br>
pressure&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Atmospheric&nbsp;pressure&nbsp;(millibars).<br>
&nbsp;<br>
Returns<br>
-------<br>
location&nbsp;:&nbsp;<a href="#OnSurface">OnSurface</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#OnSurface">OnSurface</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;the&nbsp;location&nbsp;of&nbsp;and<br>
&nbsp;&nbsp;&nbsp;&nbsp;weather&nbsp;for&nbsp;an&nbsp;observer&nbsp;on&nbsp;the&nbsp;surface&nbsp;of&nbsp;the&nbsp;Earth.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;This&nbsp;function&nbsp;is&nbsp;equivalent&nbsp;to&nbsp;calling&nbsp;the&nbsp;object&nbsp;with<br>
&nbsp;&nbsp;&nbsp;&nbsp;arguments,&nbsp;e.g.,&nbsp;<a href="#OnSurface">OnSurface</a>(latitude,&nbsp;longitude,&nbsp;height,<br>
&nbsp;&nbsp;&nbsp;&nbsp;temperature,&nbsp;pressure);&nbsp;this&nbsp;function&nbsp;exists&nbsp;for&nbsp;the&nbsp;purpose&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;direct&nbsp;compatibility&nbsp;with&nbsp;NOVAS&nbsp;C.</tt></dd></dl>
 <dl><dt><a name="-mean_obliq"><strong>mean_obliq</strong></a>(jd_tdb)</dt><dd><tt>Return&nbsp;the&nbsp;mean&nbsp;obliquity&nbsp;of&nbsp;the&nbsp;ecliptic.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tdb&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TDB&nbsp;Julian&nbsp;date.<br>
&nbsp;<br>
Returns<br>
-------<br>
epsilon&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Mean&nbsp;obliquity&nbsp;of&nbsp;the&nbsp;ecliptic&nbsp;in&nbsp;arcseconds.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Capitaine&nbsp;et&nbsp;al.&nbsp;(2003),&nbsp;Astronomy&nbsp;and&nbsp;Astrophysics&nbsp;412,<br>
&nbsp;&nbsp;&nbsp;&nbsp;567-586.</tt></dd></dl>
 <dl><dt><a name="-mean_star"><strong>mean_star</strong></a>(jd_tt, ra, dec, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Computes&nbsp;the&nbsp;ICRS&nbsp;position&nbsp;of&nbsp;a&nbsp;star,&nbsp;given&nbsp;its&nbsp;apparent&nbsp;place<br>
at&nbsp;'date'.&nbsp;Proper&nbsp;motion,&nbsp;parallax,&nbsp;and&nbsp;radial&nbsp;velocity&nbsp;are&nbsp;assumed<br>
to&nbsp;be&nbsp;zero.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date&nbsp;of&nbsp;apparent&nbsp;place.<br>
ra&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Apparent&nbsp;right&nbsp;ascension&nbsp;in&nbsp;hours,&nbsp;referred&nbsp;to&nbsp;true&nbsp;equator&nbsp;and<br>
&nbsp;&nbsp;&nbsp;&nbsp;equinox&nbsp;of&nbsp;date.<br>
dec&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Apparent&nbsp;declination&nbsp;in&nbsp;degrees,&nbsp;referred&nbsp;to&nbsp;true&nbsp;equator&nbsp;and<br>
&nbsp;&nbsp;&nbsp;&nbsp;equinox&nbsp;of&nbsp;date.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(ira,&nbsp;idec)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;ICRS&nbsp;(right&nbsp;ascension&nbsp;in&nbsp;hours,&nbsp;declination&nbsp;in&nbsp;degrees).<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Explanatory&nbsp;Supplement&nbsp;to&nbsp;the&nbsp;Astronomical&nbsp;Almanac&nbsp;(1992),<br>
&nbsp;&nbsp;&nbsp;&nbsp;Chapter&nbsp;3.</tt></dd></dl>
 <dl><dt><a name="-norm_ang"><strong>norm_ang</strong></a>(angle)</dt><dd><tt>Normalize&nbsp;angle&nbsp;into&nbsp;the&nbsp;range&nbsp;0&nbsp;&lt;=&nbsp;angle&nbsp;&lt;&nbsp;(2&nbsp;*&nbsp;pi).<br>
&nbsp;<br>
Parameters<br>
----------<br>
angle&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Input&nbsp;angle&nbsp;in&nbsp;radians.<br>
&nbsp;<br>
Returns<br>
-------<br>
norm_angle&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;The&nbsp;input&nbsp;angle,&nbsp;normalized&nbsp;as&nbsp;described&nbsp;above,&nbsp;in&nbsp;radians.</tt></dd></dl>
 <dl><dt><a name="-nutation"><strong>nutation</strong></a>(jd_tdb, position, direction<font color="#909090">=0</font>, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Nutates&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates&nbsp;from&nbsp;mean&nbsp;equator&nbsp;and<br>
equinox&nbsp;of&nbsp;epoch&nbsp;to&nbsp;true&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;epoch.&nbsp;Inverse<br>
transformation&nbsp;may&nbsp;be&nbsp;applied&nbsp;by&nbsp;setting&nbsp;flag&nbsp;'direction'.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tdb&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TDB&nbsp;Julian&nbsp;date&nbsp;of&nbsp;epoch.<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;geocentric&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates,<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;mean&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;epoch.<br>
direction&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;transform&nbsp;from&nbsp;mean&nbsp;to&nbsp;true&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;transform&nbsp;from&nbsp;true&nbsp;to&nbsp;mean<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;geocentric&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates,<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;true&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;epoch.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Explanatory&nbsp;Supplement&nbsp;To&nbsp;The&nbsp;Astronomical&nbsp;Almanac,&nbsp;pp.<br>
&nbsp;&nbsp;&nbsp;&nbsp;114-115.</tt></dd></dl>
 <dl><dt><a name="-nutation_angles"><strong>nutation_angles</strong></a>(time, accuracy<font color="#909090">=0</font>)</dt><dd><tt>This&nbsp;function&nbsp;returns&nbsp;the&nbsp;values&nbsp;for&nbsp;nutation&nbsp;in&nbsp;longitude&nbsp;and<br>
nutation&nbsp;in&nbsp;obliquity&nbsp;for&nbsp;a&nbsp;given&nbsp;TDB&nbsp;Julian&nbsp;date.&nbsp;The&nbsp;nutation<br>
model&nbsp;selected&nbsp;depends&nbsp;upon&nbsp;the&nbsp;input&nbsp;value&nbsp;of&nbsp;'accuracy'.&nbsp;See<br>
notes&nbsp;below&nbsp;for&nbsp;important&nbsp;details.<br>
&nbsp;<br>
Parameters<br>
----------<br>
time&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TDB&nbsp;time&nbsp;in&nbsp;Julian&nbsp;centuries&nbsp;since&nbsp;J2000.0<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;nutation.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(dpsi,&nbsp;deps)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Nutation&nbsp;in&nbsp;(longitude,&nbsp;obliquity)&nbsp;in&nbsp;arcseconds.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;This&nbsp;function&nbsp;selects&nbsp;the&nbsp;nutation&nbsp;model&nbsp;depending&nbsp;first<br>
&nbsp;&nbsp;&nbsp;&nbsp;upon&nbsp;the&nbsp;input&nbsp;value&nbsp;of&nbsp;'accuracy'.&nbsp;If&nbsp;'accuracy'&nbsp;=&nbsp;0&nbsp;(full<br>
&nbsp;&nbsp;&nbsp;&nbsp;accuracy),&nbsp;the&nbsp;IAU&nbsp;2000A&nbsp;nutation&nbsp;model&nbsp;is&nbsp;used.&nbsp;If&nbsp;'accuracy'<br>
&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;(reduced&nbsp;accuracy,&nbsp;the&nbsp;model&nbsp;used&nbsp;depends&nbsp;upon&nbsp;the&nbsp;value&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;local&nbsp;variable&nbsp;'low_acc_choice',&nbsp;which&nbsp;is&nbsp;set&nbsp;in&nbsp;'novas.c'.<br>
..&nbsp;[N2]&nbsp;If&nbsp;local&nbsp;variable&nbsp;'low_acc_choice'&nbsp;=&nbsp;1&nbsp;(the&nbsp;default),&nbsp;a<br>
&nbsp;&nbsp;&nbsp;&nbsp;specially&nbsp;truncated&nbsp;version&nbsp;of&nbsp;IAU&nbsp;2000A,&nbsp;called&nbsp;'NU2000K'&nbsp;is<br>
&nbsp;&nbsp;&nbsp;&nbsp;used.&nbsp;If&nbsp;'low_acc_choice'&nbsp;=&nbsp;2,&nbsp;the&nbsp;IAU&nbsp;2000B&nbsp;nutation&nbsp;model&nbsp;is<br>
&nbsp;&nbsp;&nbsp;&nbsp;used.<br>
..&nbsp;[N3]&nbsp;See&nbsp;the&nbsp;docstrings&nbsp;of&nbsp;the&nbsp;nutation&nbsp;functions&nbsp;in<br>
&nbsp;&nbsp;&nbsp;&nbsp;novas.nutation&nbsp;for&nbsp;details&nbsp;concerning&nbsp;the&nbsp;models.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Kaplan,&nbsp;G.&nbsp;(2005),&nbsp;US&nbsp;Naval&nbsp;Observatory&nbsp;Circular&nbsp;179.</tt></dd></dl>
 <dl><dt><a name="-place"><strong>place</strong></a>(jd_tt, delta_t, cel_object, location, coord_sys, accuracy<font color="#909090">=0</font>)</dt><dd><tt>This&nbsp;function&nbsp;computes&nbsp;the&nbsp;apparent&nbsp;direction&nbsp;of&nbsp;a&nbsp;star&nbsp;or&nbsp;solar<br>
system&nbsp;body&nbsp;at&nbsp;a&nbsp;specified&nbsp;time&nbsp;and&nbsp;in&nbsp;a&nbsp;specified&nbsp;coordinate<br>
system.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date&nbsp;for&nbsp;place.<br>
delta_t&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Difference&nbsp;TT-UT1&nbsp;at&nbsp;'jd_tt',&nbsp;in&nbsp;seconds&nbsp;of&nbsp;time.<br>
cel_object&nbsp;:&nbsp;<a href="#Object">Object</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#Object">Object</a>&nbsp;type&nbsp;object&nbsp;specifying&nbsp;the&nbsp;celestial&nbsp;object<br>
&nbsp;&nbsp;&nbsp;&nbsp;of&nbsp;interest.<br>
location&nbsp;:&nbsp;<a href="#Observer">Observer</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#Observer">Observer</a>&nbsp;type&nbsp;object&nbsp;specifying&nbsp;the&nbsp;location&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;observer.<br>
coord_sys&nbsp;:&nbsp;{0,&nbsp;1,&nbsp;2,&nbsp;3},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;coordinate&nbsp;system&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;GCRS&nbsp;or&nbsp;"local&nbsp;GCRS"<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;true&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;2&nbsp;...&nbsp;true&nbsp;equator&nbsp;and&nbsp;CIO&nbsp;of&nbsp;date<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;3&nbsp;...&nbsp;astrometric&nbsp;coordinates,&nbsp;i.e.,&nbsp;without&nbsp;light<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;deflection&nbsp;of&nbsp;aberration<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
output&nbsp;:&nbsp;<a href="#SkyPos">SkyPos</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#SkyPos">SkyPos</a>&nbsp;type&nbsp;object&nbsp;specifying&nbsp;object's&nbsp;place&nbsp;on&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;sky&nbsp;at&nbsp;time&nbsp;'jd_tt',&nbsp;with&nbsp;respect&nbsp;to&nbsp;the&nbsp;specified&nbsp;output<br>
&nbsp;&nbsp;&nbsp;&nbsp;coordinate&nbsp;system.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;Values&nbsp;of&nbsp;'location.where'&nbsp;and&nbsp;'coord_sys'&nbsp;dictate&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;various&nbsp;standard&nbsp;kinds&nbsp;of&nbsp;place:<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;location.where&nbsp;=&nbsp;0&nbsp;and&nbsp;system&nbsp;=&nbsp;1:&nbsp;apparent&nbsp;place<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;location.where&nbsp;=&nbsp;1&nbsp;and&nbsp;system&nbsp;=&nbsp;1:&nbsp;topocentric&nbsp;place<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;location.where&nbsp;=&nbsp;0&nbsp;and&nbsp;system&nbsp;=&nbsp;0:&nbsp;virtual&nbsp;place<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;location.where&nbsp;=&nbsp;1&nbsp;and&nbsp;system&nbsp;=&nbsp;0:&nbsp;local&nbsp;place<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;location.where&nbsp;=&nbsp;0&nbsp;and&nbsp;system&nbsp;=&nbsp;3:&nbsp;astrometric&nbsp;place<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;location.where&nbsp;=&nbsp;1&nbsp;and&nbsp;system&nbsp;=&nbsp;3:&nbsp;topocentric&nbsp;astrometric<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;place<br>
..&nbsp;[N2]&nbsp;Input&nbsp;value&nbsp;of&nbsp;'delta_t'&nbsp;is&nbsp;used&nbsp;only&nbsp;when&nbsp;'location.where'<br>
&nbsp;&nbsp;&nbsp;&nbsp;equals&nbsp;1&nbsp;or&nbsp;2&nbsp;(observer&nbsp;is&nbsp;on&nbsp;surface&nbsp;of&nbsp;Earth&nbsp;or&nbsp;in&nbsp;a<br>
&nbsp;&nbsp;&nbsp;&nbsp;near-Earth&nbsp;satellite).<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Kaplan,&nbsp;G.&nbsp;et&nbsp;al.&nbsp;(1989),&nbsp;Astronomical&nbsp;Journal&nbsp;97,<br>
&nbsp;&nbsp;&nbsp;&nbsp;1197-1210.<br>
..&nbsp;[R2]&nbsp;Klioner,&nbsp;S.&nbsp;(2003),&nbsp;Astronomical&nbsp;Journal&nbsp;125,&nbsp;1580-1597.</tt></dd></dl>
 <dl><dt><a name="-pointer"><strong>pointer</strong></a>(...)</dt></dl>
 <dl><dt><a name="-precession"><strong>precession</strong></a>(jd_tdb1, position, jd_tdb2)</dt><dd><tt>Precesses&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates&nbsp;from&nbsp;one&nbsp;epoch&nbsp;to<br>
another.&nbsp;One&nbsp;of&nbsp;the&nbsp;two&nbsp;epochs&nbsp;must&nbsp;be&nbsp;J2000.0.&nbsp;The&nbsp;coordinates<br>
are&nbsp;referred&nbsp;to&nbsp;the&nbsp;mean&nbsp;dynamical&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;the&nbsp;two<br>
respective&nbsp;epochs.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tdb1&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TDB&nbsp;Julian&nbsp;date&nbsp;of&nbsp;first&nbsp;epoch.&nbsp;See&nbsp;Note&nbsp;[N1]_&nbsp;below.<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;geocentric&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates,<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;mean&nbsp;dynamical&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;first&nbsp;epoch.<br>
jd_tdb2&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TDB&nbsp;Julian&nbsp;date&nbsp;of&nbsp;second&nbsp;epoch.&nbsp;See&nbsp;Note&nbsp;[N1]_&nbsp;below.<br>
&nbsp;<br>
Returns<br>
-------<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;geocentric&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates,<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;mean&nbsp;dynamical&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;second&nbsp;epoch.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;Either&nbsp;'date'&nbsp;or&nbsp;'newdate'&nbsp;must&nbsp;be&nbsp;2451545.0&nbsp;(J2000.0)&nbsp;TDB.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Explanatory&nbsp;Supplement&nbsp;To&nbsp;The&nbsp;Astronomical&nbsp;Almanac,&nbsp;pp.<br>
&nbsp;&nbsp;&nbsp;&nbsp;103-104.<br>
..&nbsp;[R2]&nbsp;Capitaine,&nbsp;N.&nbsp;et&nbsp;al.&nbsp;(2003),&nbsp;Astronomy&nbsp;And&nbsp;Astrophysics&nbsp;412,<br>
&nbsp;&nbsp;&nbsp;&nbsp;pp.&nbsp;567-586.<br>
..&nbsp;[R3]&nbsp;Hilton,&nbsp;J.&nbsp;L.&nbsp;et&nbsp;al.&nbsp;(2006),&nbsp;IAU&nbsp;WG&nbsp;report,&nbsp;Celest.&nbsp;Mech.,<br>
&nbsp;&nbsp;&nbsp;&nbsp;94,&nbsp;pp.&nbsp;351-367.</tt></dd></dl>
 <dl><dt><a name="-proper_motion"><strong>proper_motion</strong></a>(jd_tdb1, position, velocity, jd_tdb2)</dt><dd><tt>Applies&nbsp;proper&nbsp;motion,&nbsp;including&nbsp;foreshortening&nbsp;effects,&nbsp;to&nbsp;a&nbsp;star's<br>
position.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tdb1&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TDB&nbsp;Julian&nbsp;date&nbsp;of&nbsp;first&nbsp;epoch.<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;at&nbsp;first&nbsp;epoch.<br>
velocity&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Velocity&nbsp;vector&nbsp;at&nbsp;first&nbsp;epoch.<br>
jd_tdb2&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TDB&nbsp;Julian&nbsp;date&nbsp;of&nbsp;second&nbsp;epoch.<br>
&nbsp;<br>
Returns<br>
-------<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;at&nbsp;second&nbsp;epoch.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C16.</tt></dd></dl>
 <dl><dt><a name="-rad_vel"><strong>rad_vel</strong></a>(cel_object, pos, vel, vel_obs, distance_geo, distance_sun, distance_obj_sun)</dt><dd><tt>Predicts&nbsp;the&nbsp;radial&nbsp;velocity&nbsp;of&nbsp;the&nbsp;observed&nbsp;object&nbsp;as&nbsp;it&nbsp;would&nbsp;be<br>
measured&nbsp;by&nbsp;spectroscopic&nbsp;means.&nbsp;Radial&nbsp;velocity&nbsp;is&nbsp;here&nbsp;defined&nbsp;as<br>
the&nbsp;radial&nbsp;velocity&nbsp;measure&nbsp;(z)&nbsp;times&nbsp;the&nbsp;speed&nbsp;of&nbsp;light.&nbsp;For&nbsp;a<br>
solar&nbsp;system&nbsp;body,&nbsp;it&nbsp;applies&nbsp;to&nbsp;a&nbsp;fictitious&nbsp;emitter&nbsp;at&nbsp;the&nbsp;center<br>
of&nbsp;the&nbsp;observed&nbsp;object,&nbsp;assumed&nbsp;massless&nbsp;(no&nbsp;gravitational&nbsp;red<br>
shift),&nbsp;and&nbsp;does&nbsp;not&nbsp;in&nbsp;general&nbsp;apply&nbsp;to&nbsp;reflected&nbsp;light.&nbsp;For&nbsp;stars,<br>
it&nbsp;includes&nbsp;all&nbsp;effects,&nbsp;such&nbsp;as&nbsp;gravitational&nbsp;red&nbsp;shift,&nbsp;contained<br>
in&nbsp;the&nbsp;catalog&nbsp;barycentric&nbsp;radial&nbsp;velocity&nbsp;measure,&nbsp;a&nbsp;scalar&nbsp;derived<br>
from&nbsp;spectroscopy.&nbsp;Nearby&nbsp;stars&nbsp;with&nbsp;a&nbsp;known&nbsp;kinematic&nbsp;velocity<br>
vector&nbsp;(obtained&nbsp;independently&nbsp;of&nbsp;spectroscopy)&nbsp;can&nbsp;be&nbsp;treated&nbsp;like<br>
solar&nbsp;system&nbsp;objects.<br>
&nbsp;<br>
Parameters<br>
----------<br>
cel_object&nbsp;:&nbsp;<a href="#Object">Object</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Specifies&nbsp;the&nbsp;celestial&nbsp;object&nbsp;of&nbsp;interest.<br>
pos&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Geometric&nbsp;position&nbsp;vector&nbsp;of&nbsp;object&nbsp;with&nbsp;respect&nbsp;to&nbsp;observer,<br>
&nbsp;&nbsp;&nbsp;&nbsp;corrected&nbsp;for&nbsp;light-time,&nbsp;in&nbsp;AU.<br>
vel&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Velocity&nbsp;vector&nbsp;of&nbsp;object&nbsp;with&nbsp;respect&nbsp;to&nbsp;solar&nbsp;system<br>
&nbsp;&nbsp;&nbsp;&nbsp;barycenter,&nbsp;in&nbsp;AU/day.<br>
vel_obs&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Velocity&nbsp;vector&nbsp;of&nbsp;observer&nbsp;with&nbsp;respect&nbsp;to&nbsp;solar&nbsp;system<br>
&nbsp;&nbsp;&nbsp;&nbsp;barycenter,&nbsp;in&nbsp;AU/day.<br>
distance_geo&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Distance&nbsp;from&nbsp;observer&nbsp;to&nbsp;geocenter,&nbsp;in&nbsp;AU.<br>
distance_sun&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Distance&nbsp;from&nbsp;observer&nbsp;to&nbsp;Sun,&nbsp;in&nbsp;AU.<br>
distance_obj_sun&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Distance&nbsp;from&nbsp;object&nbsp;to&nbsp;Sun,&nbsp;in&nbsp;AU.<br>
&nbsp;<br>
Returns<br>
-------<br>
rv&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;The&nbsp;observed&nbsp;radial&nbsp;velocity&nbsp;measure&nbsp;times&nbsp;the&nbsp;speed&nbsp;of&nbsp;light,<br>
&nbsp;&nbsp;&nbsp;&nbsp;in&nbsp;kilometers/second.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;All&nbsp;the&nbsp;input&nbsp;arguments&nbsp;are&nbsp;BCRS&nbsp;quantities,&nbsp;expressed<br>
&nbsp;&nbsp;&nbsp;&nbsp;with&nbsp;respect&nbsp;to&nbsp;the&nbsp;ICRS&nbsp;axes.&nbsp;'vel'&nbsp;and&nbsp;'vel_obs'&nbsp;are<br>
&nbsp;&nbsp;&nbsp;&nbsp;kinematic&nbsp;velocities&nbsp;-&nbsp;derived&nbsp;from&nbsp;geometry&nbsp;or&nbsp;dynamics,&nbsp;not<br>
&nbsp;&nbsp;&nbsp;&nbsp;spectroscopy.<br>
..&nbsp;[N2]&nbsp;If&nbsp;the&nbsp;object&nbsp;is&nbsp;outside&nbsp;the&nbsp;solar&nbsp;system,&nbsp;the&nbsp;algorithm<br>
&nbsp;&nbsp;&nbsp;&nbsp;used&nbsp;will&nbsp;be&nbsp;consistent&nbsp;with&nbsp;the&nbsp;IAU&nbsp;definition&nbsp;of&nbsp;stellar<br>
&nbsp;&nbsp;&nbsp;&nbsp;radial&nbsp;velocity,&nbsp;specifically,&nbsp;the&nbsp;barycentric&nbsp;radial&nbsp;velocity<br>
&nbsp;&nbsp;&nbsp;&nbsp;measure,&nbsp;which&nbsp;is&nbsp;derived&nbsp;from&nbsp;spectroscopy.&nbsp;In&nbsp;that&nbsp;case,<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;vector&nbsp;'vel'&nbsp;can&nbsp;be&nbsp;very&nbsp;approximate&nbsp;--&nbsp;or,&nbsp;for&nbsp;distant<br>
&nbsp;&nbsp;&nbsp;&nbsp;stars&nbsp;or&nbsp;galaxies,&nbsp;zero&nbsp;--&nbsp;as&nbsp;it&nbsp;will&nbsp;be&nbsp;used&nbsp;only&nbsp;for&nbsp;a&nbsp;small<br>
&nbsp;&nbsp;&nbsp;&nbsp;geometric&nbsp;correction&nbsp;that&nbsp;is&nbsp;proportional&nbsp;to&nbsp;proper&nbsp;motion.<br>
..&nbsp;[N3]&nbsp;Any&nbsp;of&nbsp;the&nbsp;distances&nbsp;(last&nbsp;three&nbsp;input&nbsp;arguments)&nbsp;can&nbsp;be&nbsp;set<br>
&nbsp;&nbsp;&nbsp;&nbsp;to&nbsp;zero&nbsp;(0.0)&nbsp;if&nbsp;the&nbsp;corresponding&nbsp;general&nbsp;relativistic<br>
&nbsp;&nbsp;&nbsp;&nbsp;gravitational&nbsp;potential&nbsp;term&nbsp;is&nbsp;not&nbsp;to&nbsp;be&nbsp;evaluated.&nbsp;These&nbsp;terms<br>
&nbsp;&nbsp;&nbsp;&nbsp;generally&nbsp;are&nbsp;important&nbsp;only&nbsp;at&nbsp;the&nbsp;meter/second&nbsp;level.&nbsp;If<br>
&nbsp;&nbsp;&nbsp;&nbsp;'distance_geo'&nbsp;and&nbsp;'distance_sun'&nbsp;are&nbsp;both&nbsp;zero,&nbsp;an&nbsp;average<br>
&nbsp;&nbsp;&nbsp;&nbsp;value&nbsp;will&nbsp;be&nbsp;used&nbsp;for&nbsp;the&nbsp;relativistic&nbsp;term&nbsp;for&nbsp;the&nbsp;observer,<br>
&nbsp;&nbsp;&nbsp;&nbsp;appropriate&nbsp;for&nbsp;an&nbsp;observer&nbsp;on&nbsp;the&nbsp;surface&nbsp;of&nbsp;the&nbsp;Earth.<br>
&nbsp;&nbsp;&nbsp;&nbsp;'distance_sun',&nbsp;if&nbsp;given,&nbsp;is&nbsp;used&nbsp;only&nbsp;for&nbsp;solar&nbsp;system&nbsp;objects.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Lindegren&nbsp;&amp;&nbsp;Dravins&nbsp;(2003),&nbsp;Astronomy&nbsp;&amp;&nbsp;Astrophysics&nbsp;401,<br>
&nbsp;&nbsp;&nbsp;&nbsp;1185-1201.</tt></dd></dl>
 <dl><dt><a name="-radec2vector"><strong>radec2vector</strong></a>(ra, dec, distance)</dt><dd><tt>Converts&nbsp;equatorial&nbsp;spherical&nbsp;coordinates&nbsp;to&nbsp;a&nbsp;vector&nbsp;(equatorial<br>
rectangular&nbsp;coordinates).<br>
&nbsp;<br>
Parameters<br>
----------<br>
ra&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Right&nbsp;ascension&nbsp;in&nbsp;hours.<br>
dec&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Declination&nbsp;in&nbsp;degrees.<br>
distance&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Distance&nbsp;in&nbsp;AU.<br>
&nbsp;<br>
Returns<br>
-------<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates&nbsp;in&nbsp;AU.</tt></dd></dl>
 <dl><dt><a name="-refract"><strong>refract</strong></a>(location, zd_obs, atmosphere<font color="#909090">=1</font>)</dt><dd><tt>This&nbsp;function&nbsp;computes&nbsp;atmospheric&nbsp;refraction&nbsp;in&nbsp;zenith<br>
distance.&nbsp;This&nbsp;version&nbsp;computes&nbsp;approximate&nbsp;refraction&nbsp;for<br>
optical&nbsp;wavelengths.<br>
&nbsp;<br>
Parameters<br>
----------<br>
location&nbsp;:&nbsp;<a href="#OnSurface">OnSurface</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#OnSurface">OnSurface</a>&nbsp;type&nbsp;object&nbsp;&nbsp;containing&nbsp;observer's<br>
&nbsp;&nbsp;&nbsp;&nbsp;location.&nbsp;This&nbsp;structure&nbsp;also&nbsp;contains&nbsp;weather&nbsp;data&nbsp;(optional)<br>
&nbsp;&nbsp;&nbsp;&nbsp;for&nbsp;the&nbsp;observer's&nbsp;location.<br>
zenith&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Observed&nbsp;zenith&nbsp;distance,&nbsp;in&nbsp;degrees.<br>
atmosphere&nbsp;:&nbsp;{1,&nbsp;2},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;use&nbsp;'standard'&nbsp;atmospheric&nbsp;conditions&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;2&nbsp;...&nbsp;use&nbsp;atmospheric&nbsp;parameters&nbsp;input&nbsp;in&nbsp;the&nbsp;'location'<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;object.<br>
&nbsp;<br>
Returns<br>
-------<br>
refraction&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Atmospheric&nbsp;refraction,&nbsp;in&nbsp;degrees.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;This&nbsp;function&nbsp;can&nbsp;be&nbsp;used&nbsp;for&nbsp;planning&nbsp;observations&nbsp;or<br>
&nbsp;&nbsp;&nbsp;&nbsp;telescope&nbsp;pointing,&nbsp;but&nbsp;should&nbsp;not&nbsp;be&nbsp;used&nbsp;for&nbsp;the&nbsp;reduction<br>
&nbsp;&nbsp;&nbsp;&nbsp;of&nbsp;precise&nbsp;observations.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Explanatory&nbsp;Supplement&nbsp;to&nbsp;the&nbsp;Astronomical&nbsp;Almanac,&nbsp;p.&nbsp;144.<br>
..&nbsp;[R2]&nbsp;Bennett,&nbsp;G.&nbsp;(1982),&nbsp;Journal&nbsp;of&nbsp;Navigation&nbsp;(Royal&nbsp;Institute)<br>
&nbsp;&nbsp;&nbsp;&nbsp;35,&nbsp;pp.&nbsp;255-259.</tt></dd></dl>
 <dl><dt><a name="-resize"><strong>resize</strong></a>(...)</dt><dd><tt>Resize&nbsp;the&nbsp;memory&nbsp;buffer&nbsp;of&nbsp;a&nbsp;ctypes&nbsp;instance</tt></dd></dl>
 <dl><dt><a name="-set_conversion_mode"><strong>set_conversion_mode</strong></a>(...)</dt><dd><tt><a href="#-set_conversion_mode">set_conversion_mode</a>(encoding,&nbsp;errors)&nbsp;-&gt;&nbsp;(previous-encoding,&nbsp;previous-errors)<br>
&nbsp;<br>
Set&nbsp;the&nbsp;encoding&nbsp;and&nbsp;error&nbsp;handling&nbsp;ctypes&nbsp;uses&nbsp;when&nbsp;converting<br>
between&nbsp;unicode&nbsp;and&nbsp;strings.&nbsp;&nbsp;Returns&nbsp;the&nbsp;previous&nbsp;values.</tt></dd></dl>
 <dl><dt><a name="-set_errno"><strong>set_errno</strong></a>(...)</dt></dl>
 <dl><dt><a name="-sidereal_time"><strong>sidereal_time</strong></a>(jd_high, jd_low, delta_t, gst_type<font color="#909090">=1</font>, method<font color="#909090">=0</font>, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Computes&nbsp;the&nbsp;Greenwich&nbsp;sidereal&nbsp;time,&nbsp;either&nbsp;mean&nbsp;or&nbsp;apparent,&nbsp;at<br>
Julian&nbsp;date&nbsp;'jd_high'&nbsp;+&nbsp;'jd_low'.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_high&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;High-order&nbsp;part&nbsp;of&nbsp;UT1&nbsp;Julian&nbsp;date.<br>
jd_low&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Low-order&nbsp;part&nbsp;of&nbsp;UT1&nbsp;Julian&nbsp;date.<br>
delta_t&nbsp;&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Difference&nbsp;TT-UT1&nbsp;at&nbsp;'jd_high'&nbsp;+&nbsp;'jd_low',&nbsp;in&nbsp;seconds&nbsp;of&nbsp;time.<br>
gst_type&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;compute&nbsp;Greenwich&nbsp;mean&nbsp;sidereal&nbsp;time<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;compute&nbsp;Greenwich&nbsp;apparent&nbsp;sidereal&nbsp;time&nbsp;(default)<br>
method&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Selection&nbsp;for&nbsp;method.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;CIO-based&nbsp;method&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;equinox-based&nbsp;method<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;time.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
gst&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Greenwich&nbsp;(mean&nbsp;or&nbsp;apparent)&nbsp;sidereal&nbsp;time,&nbsp;in&nbsp;hours.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;The&nbsp;Julian&nbsp;date&nbsp;may&nbsp;be&nbsp;split&nbsp;at&nbsp;any&nbsp;point,&nbsp;but&nbsp;for&nbsp;highest<br>
&nbsp;&nbsp;&nbsp;&nbsp;precision,&nbsp;set&nbsp;'jd_high'&nbsp;to&nbsp;be&nbsp;the&nbsp;integral&nbsp;part&nbsp;of&nbsp;the&nbsp;Julian<br>
&nbsp;&nbsp;&nbsp;&nbsp;date,&nbsp;and&nbsp;set&nbsp;'jd_low'&nbsp;to&nbsp;be&nbsp;the&nbsp;fractional&nbsp;part.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Kaplan,&nbsp;G.&nbsp;(2005),&nbsp;US&nbsp;Naval&nbsp;Observatory&nbsp;Circular&nbsp;179.</tt></dd></dl>
 <dl><dt><a name="-sizeof"><strong>sizeof</strong></a>(...)</dt><dd><tt><a href="#-sizeof">sizeof</a>(C&nbsp;type)&nbsp;-&gt;&nbsp;integer<br>
<a href="#-sizeof">sizeof</a>(C&nbsp;instance)&nbsp;-&gt;&nbsp;integer<br>
Return&nbsp;the&nbsp;size&nbsp;in&nbsp;bytes&nbsp;of&nbsp;a&nbsp;C&nbsp;instance</tt></dd></dl>
 <dl><dt><a name="-spin"><strong>spin</strong></a>(angle, pos1)</dt><dd><tt>This&nbsp;function&nbsp;transforms&nbsp;a&nbsp;vector&nbsp;from&nbsp;one&nbsp;coordinate&nbsp;system&nbsp;to<br>
another&nbsp;with&nbsp;same&nbsp;origin&nbsp;and&nbsp;axes&nbsp;rotated&nbsp;about&nbsp;the&nbsp;z-axis.<br>
&nbsp;<br>
Parameters<br>
----------<br>
angle&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Angle&nbsp;of&nbsp;coordinate&nbsp;system&nbsp;rotation,&nbsp;positive&nbsp;counterclockwise<br>
&nbsp;&nbsp;&nbsp;&nbsp;when&nbsp;viewed&nbsp;from&nbsp;+z,&nbsp;in&nbsp;degrees.<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector.<br>
&nbsp;<br>
Returns<br>
-------<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector&nbsp;expressed&nbsp;in&nbsp;new&nbsp;coordinate&nbsp;system&nbsp;rotated<br>
&nbsp;&nbsp;&nbsp;&nbsp;about&nbsp;z&nbsp;by&nbsp;'angle'.</tt></dd></dl>
 <dl><dt><a name="-starvectors"><strong>starvectors</strong></a>(star)</dt><dd><tt>Converts&nbsp;angular&nbsp;quantities&nbsp;for&nbsp;stars&nbsp;to&nbsp;vectors.<br>
&nbsp;<br>
Parameters<br>
----------<br>
star&nbsp;:&nbsp;<a href="#CatEntry">CatEntry</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#CatEntry">CatEntry</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;ICRS&nbsp;catalog&nbsp;data.<br>
&nbsp;<br>
Returns<br>
-------<br>
(position,&nbsp;velocity)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;and&nbsp;velocity&nbsp;vectors&nbsp;in&nbsp;equatorial&nbsp;rectangular<br>
&nbsp;&nbsp;&nbsp;&nbsp;coordinates.&nbsp;Components&nbsp;are&nbsp;in&nbsp;AU&nbsp;and&nbsp;AU/day.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C16,&nbsp;C113.</tt></dd></dl>
 <dl><dt><a name="-tdb2tt"><strong>tdb2tt</strong></a>(tdb_jd)</dt><dd><tt>Computes&nbsp;the&nbsp;Terrestrial&nbsp;Time&nbsp;(TT)&nbsp;or&nbsp;Terrestrial&nbsp;Dynamical&nbsp;Time<br>
(TDT)&nbsp;Julian&nbsp;date&nbsp;corresponding&nbsp;to&nbsp;a&nbsp;Barycentric&nbsp;Dynamical&nbsp;Time<br>
(TDB)&nbsp;Julian&nbsp;date.<br>
&nbsp;<br>
Parameters<br>
----------<br>
tdb_jd&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TDB&nbsp;Julian&nbsp;date.<br>
&nbsp;<br>
Returns<br>
-------<br>
(tt_jd,&nbsp;secdiff)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;tt_jd&nbsp;=&nbsp;TT&nbsp;Julian&nbsp;date,&nbsp;secdiff&nbsp;=&nbsp;difference&nbsp;'tdb_jd'&nbsp;-&nbsp;'tt_jd',&nbsp;<br>
&nbsp;&nbsp;&nbsp;&nbsp;in&nbsp;seconds.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;Expression&nbsp;used&nbsp;in&nbsp;this&nbsp;function&nbsp;is&nbsp;a&nbsp;truncated&nbsp;form&nbsp;of&nbsp;a<br>
&nbsp;&nbsp;&nbsp;&nbsp;longer&nbsp;and&nbsp;more&nbsp;precise&nbsp;series&nbsp;given&nbsp;in&nbsp;the&nbsp;first&nbsp;reference<br>
&nbsp;&nbsp;&nbsp;&nbsp;[R1]_.&nbsp;The&nbsp;result&nbsp;is&nbsp;good&nbsp;to&nbsp;about&nbsp;10&nbsp;microseconds.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Fairhead,&nbsp;L.&nbsp;&amp;&nbsp;Bretagnon,&nbsp;P.&nbsp;(1990)&nbsp;Astron.&nbsp;&amp;&nbsp;Astrophys.<br>
&nbsp;&nbsp;&nbsp;&nbsp;229,&nbsp;240.<br>
..&nbsp;[R2]&nbsp;Kaplan,&nbsp;G.&nbsp;(2005),&nbsp;US&nbsp;Naval&nbsp;Observatory&nbsp;Circular&nbsp;179.</tt></dd></dl>
 <dl><dt><a name="-ter2cel"><strong>ter2cel</strong></a>(jd_ut1_high, jd_ut1_low, delta_t, xp, yp, vec1, method<font color="#909090">=0</font>, option<font color="#909090">=0</font>, accuracy<font color="#909090">=0</font>)</dt><dd><tt>This&nbsp;function&nbsp;rotates&nbsp;a&nbsp;vector&nbsp;from&nbsp;the&nbsp;terrestrial&nbsp;to&nbsp;the<br>
celestial&nbsp;system.&nbsp;Specifically,&nbsp;it&nbsp;transforms&nbsp;a&nbsp;vector&nbsp;in&nbsp;the<br>
ITRS&nbsp;(rotating&nbsp;earth-fixed&nbsp;system)&nbsp;to&nbsp;the&nbsp;GCRS&nbsp;(a&nbsp;local&nbsp;space-<br>
fixed&nbsp;system)&nbsp;by&nbsp;applying&nbsp;rotations&nbsp;for&nbsp;polar&nbsp;motion,&nbsp;Earth<br>
rotation,&nbsp;nutation,&nbsp;precession,&nbsp;and&nbsp;the&nbsp;dynamical-to-GCRS<br>
frame&nbsp;tie.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_ut1_high&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;High-order&nbsp;part&nbsp;of&nbsp;UT1&nbsp;Julian&nbsp;date.<br>
jd_ut1_low&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Low-order&nbsp;part&nbsp;of&nbsp;UT1&nbsp;Julian&nbsp;date.<br>
delta_t&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Value&nbsp;of&nbsp;Delta&nbsp;T&nbsp;(=TT-UT1)&nbsp;at&nbsp;the&nbsp;input&nbsp;UT1&nbsp;Julian&nbsp;date.<br>
xp&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Conventionally-defined&nbsp;X&nbsp;coordinate&nbsp;of&nbsp;celestial&nbsp;intermediate<br>
&nbsp;&nbsp;&nbsp;&nbsp;pole&nbsp;with&nbsp;respect&nbsp;to&nbsp;ITRS&nbsp;pole,&nbsp;in&nbsp;arcseconds.<br>
yp&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Conventionally-defined&nbsp;Y&nbsp;coordinate&nbsp;of&nbsp;celestial&nbsp;intermediate<br>
&nbsp;&nbsp;&nbsp;&nbsp;pole&nbsp;with&nbsp;respect&nbsp;to&nbsp;ITRS&nbsp;pole,&nbsp;in&nbsp;arcseconds.<br>
vec1&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;geocentric&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates,<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;ITRS&nbsp;axes&nbsp;(terrestrial&nbsp;system)&nbsp;in&nbsp;the&nbsp;normal&nbsp;case<br>
&nbsp;&nbsp;&nbsp;&nbsp;where&nbsp;'option'&nbsp;=&nbsp;0.<br>
method&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Selection&nbsp;for&nbsp;method.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;CIO-based&nbsp;method&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;equinox-based&nbsp;method<br>
option&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Selection&nbsp;for&nbsp;reference&nbsp;axes<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;The&nbsp;output&nbsp;vector&nbsp;is&nbsp;referred&nbsp;to&nbsp;GCRS&nbsp;axes.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;The&nbsp;output&nbsp;vector&nbsp;is&nbsp;produced&nbsp;with&nbsp;respect&nbsp;to&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date.&nbsp;See&nbsp;Note&nbsp;[N2]_&nbsp;below.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
vec2&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;geocentric&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates,<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;GCRS&nbsp;axes&nbsp;(celestial&nbsp;system)&nbsp;or&nbsp;with&nbsp;respect&nbsp;to<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date,&nbsp;depending&nbsp;on&nbsp;'option'.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;'xp'&nbsp;=&nbsp;'yp'&nbsp;=&nbsp;0&nbsp;means&nbsp;no&nbsp;polar&nbsp;motion&nbsp;transformation.<br>
..&nbsp;[N2]&nbsp;The&nbsp;'option'&nbsp;flag&nbsp;only&nbsp;works&nbsp;for&nbsp;the&nbsp;equinox-based&nbsp;method.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C53-C54.<br>
..&nbsp;[R2]&nbsp;Kaplan,&nbsp;G.&nbsp;H.&nbsp;(2003),&nbsp;'Another&nbsp;Look&nbsp;at&nbsp;Non-Rotating<br>
&nbsp;&nbsp;&nbsp;&nbsp;Origins',&nbsp;Proceedings&nbsp;of&nbsp;IAU&nbsp;XXV&nbsp;Joint&nbsp;Discussion&nbsp;16.</tt></dd></dl>
 <dl><dt><a name="-terra"><strong>terra</strong></a>(location, time)</dt><dd><tt>Computes&nbsp;the&nbsp;position&nbsp;and&nbsp;velocity&nbsp;vectors&nbsp;of&nbsp;a&nbsp;terrestrial&nbsp;observer<br>
with&nbsp;respect&nbsp;to&nbsp;the&nbsp;center&nbsp;of&nbsp;the&nbsp;Earth.<br>
&nbsp;<br>
Parameters<br>
----------<br>
location&nbsp;:&nbsp;<a href="#OnSurface">OnSurface</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#OnSurface">OnSurface</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;observer's<br>
&nbsp;&nbsp;&nbsp;&nbsp;location.<br>
time&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Local&nbsp;apparent&nbsp;sidereal&nbsp;time&nbsp;at&nbsp;reference&nbsp;meridian&nbsp;in&nbsp;hours.<br>
&nbsp;<br>
Returns<br>
-------<br>
(position,&nbsp;velocity)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;and&nbsp;velocity&nbsp;vector&nbsp;of&nbsp;observer&nbsp;with&nbsp;respect&nbsp;to&nbsp;center<br>
&nbsp;&nbsp;&nbsp;&nbsp;of&nbsp;Earth&nbsp;in&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates,&nbsp;referred&nbsp;to&nbsp;true<br>
&nbsp;&nbsp;&nbsp;&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date.&nbsp;Components&nbsp;in&nbsp;AU&nbsp;and&nbsp;AU/day.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;If&nbsp;reference&nbsp;meridian&nbsp;is&nbsp;Greenwich&nbsp;and&nbsp;st=0,&nbsp;'pos'&nbsp;is<br>
&nbsp;&nbsp;&nbsp;&nbsp;effectively&nbsp;referred&nbsp;to&nbsp;equator&nbsp;and&nbsp;Greenwich.<br>
..&nbsp;[N2]&nbsp;This&nbsp;function&nbsp;ignores&nbsp;polar&nbsp;motion,&nbsp;unless&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;observer's&nbsp;longitude&nbsp;and&nbsp;latitude&nbsp;have&nbsp;been&nbsp;corrected&nbsp;for&nbsp;it,<br>
&nbsp;&nbsp;&nbsp;&nbsp;and&nbsp;variation&nbsp;in&nbsp;the&nbsp;length&nbsp;of&nbsp;day&nbsp;(angular&nbsp;velocity&nbsp;of&nbsp;earth).<br>
..&nbsp;[N3]&nbsp;The&nbsp;true&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date&nbsp;do&nbsp;not&nbsp;form&nbsp;an<br>
&nbsp;&nbsp;&nbsp;&nbsp;inertial&nbsp;system.&nbsp;Therefore,&nbsp;with&nbsp;respect&nbsp;to&nbsp;an&nbsp;inertial&nbsp;system,<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;very&nbsp;small&nbsp;velocity&nbsp;component&nbsp;(several&nbsp;meters/day)&nbsp;due&nbsp;to<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;precession&nbsp;and&nbsp;nutation&nbsp;of&nbsp;the&nbsp;Earth's&nbsp;axis&nbsp;is&nbsp;not&nbsp;accounted<br>
&nbsp;&nbsp;&nbsp;&nbsp;for&nbsp;here.</tt></dd></dl>
 <dl><dt><a name="-topo_planet"><strong>topo_planet</strong></a>(jd_tt, delta_t, ss_body, position, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Computes&nbsp;the&nbsp;topocentric&nbsp;place&nbsp;of&nbsp;a&nbsp;solar&nbsp;system&nbsp;body.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date&nbsp;for&nbsp;topocentric&nbsp;place.<br>
delta_t&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Difference&nbsp;TT-UT1&nbsp;at&nbsp;'date',&nbsp;in&nbsp;seconds&nbsp;of&nbsp;time.<br>
ss_body&nbsp;:&nbsp;<a href="#Object">Object</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#Object">Object</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;the&nbsp;body&nbsp;designation<br>
&nbsp;&nbsp;&nbsp;&nbsp;for&nbsp;solar&nbsp;system&nbsp;body.<br>
position&nbsp;:&nbsp;<a href="#OnSurface">OnSurface</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#OnSurface">OnSurface</a>&nbsp;type&nbsp;object&nbsp;&nbsp;specifying&nbsp;the&nbsp;position&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;observer.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(ra,&nbsp;dec,&nbsp;dis)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Topocentric&nbsp;(right&nbsp;ascension&nbsp;in&nbsp;hours,&nbsp;declination&nbsp;in&nbsp;degrees,<br>
&nbsp;&nbsp;&nbsp;&nbsp;...),&nbsp;referred&nbsp;to&nbsp;true&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date,&nbsp;and&nbsp;true<br>
&nbsp;&nbsp;&nbsp;&nbsp;(...,&nbsp;...,&nbsp;distance&nbsp;in&nbsp;AU)&nbsp;from&nbsp;Earth&nbsp;to&nbsp;solar&nbsp;system&nbsp;body&nbsp;at<br>
&nbsp;&nbsp;&nbsp;&nbsp;'jd_tt'.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C68-C69.<br>
..&nbsp;[R2]&nbsp;Explanatory&nbsp;Supplement&nbsp;to&nbsp;the&nbsp;Astronomical&nbsp;Almanac&nbsp;(1992),<br>
&nbsp;&nbsp;&nbsp;&nbsp;Chapter&nbsp;3.</tt></dd></dl>
 <dl><dt><a name="-topo_star"><strong>topo_star</strong></a>(jd_tt, delta_t, star, position, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Computes&nbsp;the&nbsp;topocentric&nbsp;place&nbsp;of&nbsp;a&nbsp;star&nbsp;at&nbsp;'date',&nbsp;given&nbsp;its<br>
catalog&nbsp;mean&nbsp;place,&nbsp;proper&nbsp;motion,&nbsp;parallax,&nbsp;and&nbsp;radial&nbsp;velocity.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date&nbsp;for&nbsp;topocentric&nbsp;place.<br>
delta_t&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Difference&nbsp;TT-UT1&nbsp;at&nbsp;'date',&nbsp;in&nbsp;seconds&nbsp;of&nbsp;time.<br>
star&nbsp;:&nbsp;<a href="#CatEntry">CatEntry</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#CatEntry">CatEntry</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;catalog&nbsp;data&nbsp;for<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;object&nbsp;in&nbsp;the&nbsp;ICRS.<br>
position&nbsp;:&nbsp;<a href="#OnSurface">OnSurface</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#OnSurface">OnSurface</a>&nbsp;type&nbsp;object&nbsp;specifying&nbsp;the&nbsp;position&nbsp;of<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;observer.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(ra,&nbsp;dec)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Topocentric&nbsp;(right&nbsp;ascension&nbsp;in&nbsp;hours,&nbsp;declination&nbsp;in&nbsp;degrees),<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;true&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;date&nbsp;'jd_tt'.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C62-C63.<br>
..&nbsp;[R2]&nbsp;Explanatory&nbsp;Supplement&nbsp;to&nbsp;the&nbsp;Astronomical&nbsp;Almanac&nbsp;(1992),<br>
&nbsp;&nbsp;&nbsp;&nbsp;Chapter&nbsp;3.</tt></dd></dl>
 <dl><dt><a name="-transform_cat"><strong>transform_cat</strong></a>(option, date_incat, incat, date_newcat, newcat_id)</dt><dd><tt>To&nbsp;transform&nbsp;a&nbsp;star's&nbsp;catalog&nbsp;quantities&nbsp;for&nbsp;a&nbsp;change&nbsp;of&nbsp;epoch<br>
and/or&nbsp;equator&nbsp;and&nbsp;equinox.&nbsp;Also&nbsp;used&nbsp;to&nbsp;rotate&nbsp;catalog<br>
quantities&nbsp;on&nbsp;the&nbsp;dynamical&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;J2000.0&nbsp;to&nbsp;the<br>
ICRS&nbsp;or&nbsp;vice&nbsp;versa.<br>
&nbsp;<br>
Parameters<br>
----------<br>
option&nbsp;:&nbsp;{1,&nbsp;2,&nbsp;3,&nbsp;4,&nbsp;5}<br>
&nbsp;&nbsp;&nbsp;&nbsp;Transformation&nbsp;option<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;change&nbsp;epoch;&nbsp;same&nbsp;equator&nbsp;and&nbsp;equinox<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;2&nbsp;...&nbsp;change&nbsp;equator&nbsp;and&nbsp;equinox;&nbsp;same&nbsp;epoch<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;3&nbsp;...&nbsp;change&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;and&nbsp;epoch<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;4&nbsp;...&nbsp;change&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;J2000.0&nbsp;to&nbsp;ICRS<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;5&nbsp;...&nbsp;change&nbsp;ICRS&nbsp;to&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;J2000.0<br>
date_incat&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date,&nbsp;or&nbsp;year,&nbsp;of&nbsp;input&nbsp;catalog&nbsp;data.<br>
incat&nbsp;:&nbsp;<a href="#CatEntry">CatEntry</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#CatEntry">CatEntry</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;an&nbsp;entry&nbsp;from&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;input&nbsp;catalog,&nbsp;with&nbsp;units&nbsp;as&nbsp;given&nbsp;in&nbsp;the&nbsp;type&nbsp;definition.<br>
date_newcat&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date,&nbsp;or&nbsp;year,&nbsp;of&nbsp;transformed&nbsp;catalog&nbsp;data.<br>
newcat_id&nbsp;:&nbsp;string<br>
&nbsp;&nbsp;&nbsp;&nbsp;Abbreviated&nbsp;name&nbsp;of&nbsp;the&nbsp;transformed&nbsp;catalog.&nbsp;Max&nbsp;length<br>
&nbsp;&nbsp;&nbsp;&nbsp;determined&nbsp;by&nbsp;SIZE_OF_CAT_NAME&nbsp;defined&nbsp;in&nbsp;``novas.h``;&nbsp;defaults<br>
&nbsp;&nbsp;&nbsp;&nbsp;to&nbsp;3.<br>
&nbsp;<br>
Returns<br>
-------<br>
newcat&nbsp;:&nbsp;<a href="#CatEntry">CatEntry</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#CatEntry">CatEntry</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;the&nbsp;transformed<br>
&nbsp;&nbsp;&nbsp;&nbsp;catalog&nbsp;entry,&nbsp;with&nbsp;units&nbsp;as&nbsp;given&nbsp;in&nbsp;the&nbsp;type&nbsp;definition.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;'date_incat'&nbsp;and&nbsp;'date_newcat'&nbsp;may&nbsp;be&nbsp;specified&nbsp;either&nbsp;as&nbsp;a<br>
&nbsp;&nbsp;&nbsp;&nbsp;Julian&nbsp;date&nbsp;(e.g.,&nbsp;2433282.5)&nbsp;or&nbsp;a&nbsp;Julian&nbsp;year&nbsp;and&nbsp;fraction<br>
&nbsp;&nbsp;&nbsp;&nbsp;(e.g.,&nbsp;1950.0).&nbsp;Values&nbsp;less&nbsp;than&nbsp;10000&nbsp;are&nbsp;assumed&nbsp;to&nbsp;be&nbsp;years.<br>
&nbsp;&nbsp;&nbsp;&nbsp;For&nbsp;'option'&nbsp;=&nbsp;2&nbsp;or&nbsp;'option'&nbsp;=&nbsp;3,&nbsp;either&nbsp;'date_incat'&nbsp;or<br>
&nbsp;&nbsp;&nbsp;&nbsp;'date_newcat'&nbsp;must&nbsp;be&nbsp;2451545.0&nbsp;or&nbsp;2000.0&nbsp;(J2000.0).&nbsp;For<br>
&nbsp;&nbsp;&nbsp;&nbsp;'option'&nbsp;=&nbsp;4&nbsp;and&nbsp;'option'&nbsp;=&nbsp;5,&nbsp;'date_incat'&nbsp;and&nbsp;'date_newcat'<br>
&nbsp;&nbsp;&nbsp;&nbsp;are&nbsp;ignored.<br>
..&nbsp;[N2]&nbsp;'option'&nbsp;=&nbsp;1&nbsp;updates&nbsp;the&nbsp;star's&nbsp;data&nbsp;to&nbsp;account&nbsp;for&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;star's&nbsp;space&nbsp;motion&nbsp;between&nbsp;the&nbsp;first&nbsp;and&nbsp;second&nbsp;dates,&nbsp;within&nbsp;a<br>
&nbsp;&nbsp;&nbsp;&nbsp;fixed&nbsp;reference&nbsp;frame.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'option'&nbsp;=&nbsp;2&nbsp;applies&nbsp;a&nbsp;rotation&nbsp;of&nbsp;the&nbsp;reference&nbsp;frame<br>
&nbsp;&nbsp;&nbsp;&nbsp;corresponding&nbsp;to&nbsp;precession&nbsp;between&nbsp;the&nbsp;first&nbsp;and&nbsp;second&nbsp;dates,<br>
&nbsp;&nbsp;&nbsp;&nbsp;but&nbsp;leaves&nbsp;the&nbsp;star&nbsp;fixed&nbsp;in&nbsp;space.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'option'&nbsp;=&nbsp;3&nbsp;provides&nbsp;both&nbsp;transformations.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'option'&nbsp;=&nbsp;4&nbsp;and&nbsp;'option'&nbsp;=&nbsp;5&nbsp;provide&nbsp;a&nbsp;a&nbsp;fixed&nbsp;rotation<br>
&nbsp;&nbsp;&nbsp;&nbsp;about&nbsp;very&nbsp;small&nbsp;angles&nbsp;(&lt;0.1&nbsp;arcsecond)&nbsp;to&nbsp;take&nbsp;data&nbsp;from&nbsp;the<br>
&nbsp;&nbsp;&nbsp;&nbsp;dynamical&nbsp;system&nbsp;of&nbsp;J2000.0&nbsp;to&nbsp;the&nbsp;ICRS&nbsp;('option'&nbsp;=&nbsp;4)&nbsp;or&nbsp;vice<br>
&nbsp;&nbsp;&nbsp;&nbsp;versa&nbsp;('option'&nbsp;=&nbsp;5).<br>
..&nbsp;[N3]&nbsp;For&nbsp;'option'&nbsp;=&nbsp;1,&nbsp;input&nbsp;data&nbsp;can&nbsp;be&nbsp;in&nbsp;any&nbsp;fixed&nbsp;reference<br>
&nbsp;&nbsp;&nbsp;&nbsp;system.&nbsp;for&nbsp;'option'&nbsp;=&nbsp;2&nbsp;or&nbsp;'option'&nbsp;=&nbsp;3,&nbsp;this&nbsp;function&nbsp;assumes<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;input&nbsp;data&nbsp;is&nbsp;in&nbsp;the&nbsp;dynamical&nbsp;system&nbsp;and&nbsp;produces&nbsp;output&nbsp;in<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;dynamical&nbsp;system.&nbsp;for&nbsp;'option'&nbsp;=&nbsp;4,&nbsp;the&nbsp;input&nbsp;data&nbsp;must&nbsp;be<br>
&nbsp;&nbsp;&nbsp;&nbsp;on&nbsp;the&nbsp;dynamical&nbsp;equator&nbsp;and&nbsp;equinox&nbsp;of&nbsp;J2000.0.&nbsp;for<br>
&nbsp;&nbsp;&nbsp;'option'&nbsp;=&nbsp;5,&nbsp;the&nbsp;input&nbsp;data&nbsp;must&nbsp;be&nbsp;in&nbsp;the&nbsp;ICRS.<br>
..&nbsp;[N4]&nbsp;This&nbsp;function&nbsp;cannot&nbsp;be&nbsp;properly&nbsp;used&nbsp;to&nbsp;bring&nbsp;data&nbsp;from<br>
&nbsp;&nbsp;&nbsp;&nbsp;old&nbsp;star&nbsp;catalogs&nbsp;into&nbsp;the&nbsp;modern&nbsp;system,&nbsp;because&nbsp;old&nbsp;catalogs<br>
&nbsp;&nbsp;&nbsp;&nbsp;were&nbsp;compiled&nbsp;using&nbsp;a&nbsp;set&nbsp;of&nbsp;constants&nbsp;that&nbsp;are<br>
&nbsp;&nbsp;&nbsp;&nbsp;incompatible&nbsp;with&nbsp;modern&nbsp;values.&nbsp;In&nbsp;particular,&nbsp;it&nbsp;should&nbsp;not<br>
&nbsp;&nbsp;&nbsp;&nbsp;be&nbsp;used&nbsp;for&nbsp;catalogs&nbsp;whose&nbsp;positions&nbsp;and&nbsp;proper&nbsp;motions&nbsp;were<br>
&nbsp;&nbsp;&nbsp;&nbsp;derived&nbsp;by&nbsp;assuming&nbsp;a&nbsp;precession&nbsp;constant&nbsp;significantly<br>
&nbsp;&nbsp;&nbsp;&nbsp;different&nbsp;from&nbsp;the&nbsp;value&nbsp;implicit&nbsp;in&nbsp;function&nbsp;'precession'.</tt></dd></dl>
 <dl><dt><a name="-transform_hip"><strong>transform_hip</strong></a>(hipparcos)</dt><dd><tt>To&nbsp;convert&nbsp;Hipparcos&nbsp;catalog&nbsp;data&nbsp;at&nbsp;epoch&nbsp;J1991.25&nbsp;to&nbsp;epoch<br>
J2000.0,&nbsp;for&nbsp;use&nbsp;within&nbsp;NOVAS.&nbsp;To&nbsp;be&nbsp;used&nbsp;only&nbsp;for&nbsp;Hipparcos&nbsp;or<br>
Tycho&nbsp;stars&nbsp;with&nbsp;linear&nbsp;space&nbsp;motion.&nbsp;Both&nbsp;input&nbsp;and&nbsp;output&nbsp;data<br>
is&nbsp;in&nbsp;the&nbsp;ICRS.<br>
&nbsp;<br>
Parameters<br>
----------<br>
hipparcos&nbsp;:&nbsp;<a href="#CatEntry">CatEntry</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#CatEntry">CatEntry</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;an&nbsp;entry&nbsp;from<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;Hipparcos&nbsp;catalog,&nbsp;at&nbsp;epoch&nbsp;J1991.25,&nbsp;with&nbsp;all&nbsp;members<br>
&nbsp;&nbsp;&nbsp;&nbsp;having&nbsp;Hipparcos&nbsp;catalog&nbsp;units.&nbsp;See&nbsp;Note&nbsp;[N1]_&nbsp;below.<br>
&nbsp;<br>
Returns<br>
-------<br>
hip_2000&nbsp;:&nbsp;<a href="#CatEntry">CatEntry</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#CatEntry">CatEntry</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;the&nbsp;transformed<br>
&nbsp;&nbsp;&nbsp;&nbsp;input&nbsp;entry,&nbsp;at&nbsp;epoch&nbsp;J2000.0.&nbsp;See&nbsp;Note&nbsp;[N2]_&nbsp;below.<br>
&nbsp;<br>
Notes<br>
-----<br>
..&nbsp;[N1]&nbsp;Input&nbsp;(Hipparcos&nbsp;catalog)&nbsp;epoch&nbsp;and&nbsp;units:<br>
&nbsp;&nbsp;&nbsp;&nbsp;Epoch:&nbsp;J1991.25<br>
&nbsp;&nbsp;&nbsp;&nbsp;Right&nbsp;ascension&nbsp;(RA):&nbsp;degrees<br>
&nbsp;&nbsp;&nbsp;&nbsp;Declination&nbsp;(Dec):&nbsp;degrees<br>
&nbsp;&nbsp;&nbsp;&nbsp;Proper&nbsp;motion&nbsp;in&nbsp;RA:&nbsp;milliarcseconds&nbsp;per&nbsp;year<br>
&nbsp;&nbsp;&nbsp;&nbsp;Proper&nbsp;motion&nbsp;in&nbsp;Dec:&nbsp;milliarcseconds&nbsp;per&nbsp;year<br>
&nbsp;&nbsp;&nbsp;&nbsp;Parallax:&nbsp;milliarcseconds<br>
&nbsp;&nbsp;&nbsp;&nbsp;Radial&nbsp;velocity:&nbsp;kilometers&nbsp;per&nbsp;second&nbsp;(not&nbsp;in&nbsp;catalog)<br>
..&nbsp;[N2]&nbsp;Output&nbsp;(modified&nbsp;Hipparcos)&nbsp;epoch&nbsp;and&nbsp;units:<br>
&nbsp;&nbsp;&nbsp;&nbsp;Epoch:&nbsp;J2000.0<br>
&nbsp;&nbsp;&nbsp;&nbsp;Right&nbsp;ascension:&nbsp;hours<br>
&nbsp;&nbsp;&nbsp;&nbsp;Declination:&nbsp;degrees<br>
&nbsp;&nbsp;&nbsp;&nbsp;Proper&nbsp;motion&nbsp;in&nbsp;RA:&nbsp;milliarcseconds&nbsp;per&nbsp;year<br>
&nbsp;&nbsp;&nbsp;&nbsp;Proper&nbsp;motion&nbsp;in&nbsp;Dec:&nbsp;milliarcseconds&nbsp;per&nbsp;year<br>
&nbsp;&nbsp;&nbsp;&nbsp;Parallax:&nbsp;milliarcseconds<br>
&nbsp;&nbsp;&nbsp;&nbsp;Radial&nbsp;velocity:&nbsp;kilometers&nbsp;per&nbsp;second</tt></dd></dl>
 <dl><dt><a name="-vector2radec"><strong>vector2radec</strong></a>(position)</dt><dd><tt>Converts&nbsp;an&nbsp;vector&nbsp;in&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates&nbsp;to<br>
equatorial&nbsp;spherical&nbsp;coordinates.<br>
&nbsp;<br>
Parameters<br>
----------<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates.<br>
&nbsp;<br>
Returns<br>
-------<br>
(rightascension,&nbsp;declination)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;(Right&nbsp;ascension&nbsp;in&nbsp;hours,&nbsp;declination&nbsp;in&nbsp;degrees)<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C38-C39.</tt></dd></dl>
 <dl><dt><a name="-virtual_planet"><strong>virtual_planet</strong></a>(jd_tt, ss_body, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Compute&nbsp;the&nbsp;virtual&nbsp;place&nbsp;of&nbsp;a&nbsp;planet&nbsp;or&nbsp;other&nbsp;solar&nbsp;system&nbsp;body.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date&nbsp;for&nbsp;virtual&nbsp;place.<br>
ss_body&nbsp;:&nbsp;<a href="#Object">Object</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#Object">Object</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;the&nbsp;body&nbsp;designation<br>
&nbsp;&nbsp;&nbsp;&nbsp;for&nbsp;the&nbsp;solar&nbsp;system&nbsp;body.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(ra,&nbsp;dec,&nbsp;dis)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Virtual&nbsp;(right&nbsp;ascension&nbsp;in&nbsp;hours,&nbsp;declination&nbsp;in&nbsp;degrees,&nbsp;...),<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;the&nbsp;GCRS,&nbsp;and&nbsp;true&nbsp;(...,&nbsp;...,&nbsp;distance&nbsp;in&nbsp;AU)<br>
&nbsp;&nbsp;&nbsp;&nbsp;from&nbsp;Earth&nbsp;to&nbsp;solar&nbsp;system&nbsp;body.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C70.<br>
..&nbsp;[R2]&nbsp;Explanatory&nbsp;Supplement&nbsp;to&nbsp;the&nbsp;Astronomical&nbsp;Almanac&nbsp;(1992),<br>
&nbsp;&nbsp;&nbsp;&nbsp;Chapter&nbsp;3.</tt></dd></dl>
 <dl><dt><a name="-virtual_star"><strong>virtual_star</strong></a>(jd_tt, star, accuracy<font color="#909090">=0</font>)</dt><dd><tt>Computes&nbsp;the&nbsp;virtual&nbsp;place&nbsp;of&nbsp;a&nbsp;star&nbsp;at&nbsp;'date',&nbsp;given&nbsp;its&nbsp;catalog<br>
mean&nbsp;place,&nbsp;proper&nbsp;motion,&nbsp;parallax,&nbsp;and&nbsp;radial&nbsp;velocity.<br>
&nbsp;<br>
Parameters<br>
----------<br>
jd_tt&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;Julian&nbsp;date&nbsp;for&nbsp;virtual&nbsp;place.<br>
star&nbsp;:&nbsp;<a href="#CatEntry">CatEntry</a><br>
&nbsp;&nbsp;&nbsp;&nbsp;Instance&nbsp;of&nbsp;<a href="#CatEntry">CatEntry</a>&nbsp;type&nbsp;object&nbsp;containing&nbsp;catalog&nbsp;data&nbsp;for<br>
&nbsp;&nbsp;&nbsp;&nbsp;the&nbsp;object&nbsp;in&nbsp;the&nbsp;ICRS.<br>
accuracy&nbsp;:&nbsp;{0,&nbsp;1},&nbsp;optional<br>
&nbsp;&nbsp;&nbsp;&nbsp;Code&nbsp;specifying&nbsp;the&nbsp;relative&nbsp;accuracy&nbsp;of&nbsp;the&nbsp;output&nbsp;position.<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;0&nbsp;...&nbsp;full&nbsp;accuracy&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=&nbsp;1&nbsp;...&nbsp;reduced&nbsp;accuracy<br>
&nbsp;<br>
Returns<br>
-------<br>
(ra,&nbsp;dec)&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats<br>
&nbsp;&nbsp;&nbsp;&nbsp;Virtual&nbsp;(right&nbsp;ascension&nbsp;in&nbsp;hours,&nbsp;declination&nbsp;in&nbsp;degrees),<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;the&nbsp;GCRS.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C64.<br>
..&nbsp;[R2]&nbsp;Explanatory&nbsp;Supplement&nbsp;to&nbsp;the&nbsp;Astronomical&nbsp;Almanac&nbsp;(1992),<br>
&nbsp;&nbsp;&nbsp;&nbsp;Chapter&nbsp;3.</tt></dd></dl>
 <dl><dt><a name="-wobble"><strong>wobble</strong></a>(tjd, x, y, position, direction<font color="#909090">=0</font>)</dt><dd><tt>Corrects&nbsp;a&nbsp;vector&nbsp;in&nbsp;the&nbsp;ICRS&nbsp;(rotating&nbsp;Earth-fixed&nbsp;system)&nbsp;for<br>
polar&nbsp;motion,&nbsp;and&nbsp;also&nbsp;corrects&nbsp;the&nbsp;longitude&nbsp;origin&nbsp;(by&nbsp;a&nbsp;tiny<br>
amount)&nbsp;to&nbsp;the&nbsp;Terrestrial&nbsp;Intermediate&nbsp;Origin&nbsp;(TIO).&nbsp;The&nbsp;ICRS<br>
vector&nbsp;is&nbsp;thereby&nbsp;transformed&nbsp;to&nbsp;the&nbsp;system&nbsp;based&nbsp;on&nbsp;the&nbsp;true<br>
(rotational)&nbsp;equator&nbsp;and&nbsp;TIO.&nbsp;Since&nbsp;the&nbsp;true&nbsp;equator&nbsp;is&nbsp;the&nbsp;plane<br>
orthogonal&nbsp;to&nbsp;the&nbsp;direction&nbsp;of&nbsp;the&nbsp;Celestial&nbsp;Intermediate&nbsp;Pole<br>
(CIP),&nbsp;the&nbsp;components&nbsp;of&nbsp;the&nbsp;output&nbsp;vector&nbsp;are&nbsp;referred&nbsp;to&nbsp;Z&nbsp;and&nbsp;X<br>
axes&nbsp;toward&nbsp;the&nbsp;CIP&nbsp;and&nbsp;TIO,&nbsp;respectively.<br>
&nbsp;<br>
Parameters<br>
----------<br>
tjd&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;TT&nbsp;or&nbsp;UT1&nbsp;Julian&nbsp;date.<br>
xp&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Conventionally-defined&nbsp;X&nbsp;coordinate&nbsp;of&nbsp;Celestial&nbsp;Intermediate<br>
&nbsp;&nbsp;&nbsp;&nbsp;Pole&nbsp;with&nbsp;respect&nbsp;to&nbsp;ICRS&nbsp;pole,&nbsp;in&nbsp;arcseconds.<br>
yp&nbsp;:&nbsp;float<br>
&nbsp;&nbsp;&nbsp;&nbsp;Conventionally&nbsp;defined&nbsp;Y&nbsp;coordinate&nbsp;of&nbsp;Celestial&nbsp;Intermediate<br>
&nbsp;&nbsp;&nbsp;&nbsp;Pole&nbsp;with&nbsp;respect&nbsp;to&nbsp;ICRS&nbsp;pole,&nbsp;in&nbsp;arcseconds.<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;geocentric&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates,<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;ITRF&nbsp;axes.<br>
direction:&nbsp;short&nbsp;int<br>
&nbsp;&nbsp;&nbsp;&nbsp;Flag&nbsp;determining&nbsp;'direction'&nbsp;of&nbsp;transformation;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;direction&nbsp;=&nbsp;0&nbsp;transformation&nbsp;applied,&nbsp;ICRS&nbsp;to&nbsp;terrestrial<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;intermediate&nbsp;system&nbsp;(default)<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;direction&nbsp;!=&nbsp;0&nbsp;inverse&nbsp;transformation&nbsp;applied,&nbsp;terrestrial<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;intermediate&nbsp;system&nbsp;to&nbsp;ICRS<br>
&nbsp;<br>
Returns<br>
-------<br>
position&nbsp;:&nbsp;tuple&nbsp;of&nbsp;floats,&nbsp;of&nbsp;length&nbsp;3<br>
&nbsp;&nbsp;&nbsp;&nbsp;Position&nbsp;vector,&nbsp;geocentric&nbsp;equatorial&nbsp;rectangular&nbsp;coordinates,<br>
&nbsp;&nbsp;&nbsp;&nbsp;referred&nbsp;to&nbsp;true&nbsp;equator&nbsp;and&nbsp;TIO.<br>
&nbsp;<br>
References<br>
----------<br>
..&nbsp;[R1]&nbsp;Bangert,&nbsp;J.&nbsp;et.&nbsp;al.&nbsp;(2011),&nbsp;'User's&nbsp;Guide&nbsp;to&nbsp;NOVAS&nbsp;Version<br>
&nbsp;&nbsp;&nbsp;&nbsp;C3.1',&nbsp;C23,&nbsp;C110,&nbsp;C111,&nbsp;C113,&nbsp;C114.<br>
..&nbsp;[R2]&nbsp;Lambert&nbsp;&amp;&nbsp;Bizouard&nbsp;(2002),&nbsp;Astronomy&nbsp;and&nbsp;Astrophysics&nbsp;394,<br>
&nbsp;&nbsp;&nbsp;&nbsp;317-321.</tt></dd></dl>
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