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README.V10 - README file for the USNO-A1 Catalog

USNO  A1.0 November 1996
USNO SA1.0 December 1996

This file is the first level of the on-board documentation.  Please
read this file first.  Near the end of this file is a list of other files
that might be helpful.  Questions and comments should be directed to

   Dave Monet
   US Naval Observatory Flagstaff Station
   10391 West Naval Observatory Rd.
   Flagstaff AZ 86001

   Voice: 928-779-5132
   FAX:   928-774-3626

Please understand that the level of support provided will be commensurate
with the level of effort expended.  I am too busy to do your homework
for you.  E-mail works better than the phone.

============ Title ====================

                    USNO-A V1.0
              A Catalog of Astrometric Standards

                   David Monet a)

        Alan Bird a), Blaise Canzian b), Hugh Harris a), Neill Reid c),
        Albert Rhodes a), Stephen Sell a),

        Harold Ables d), Conard Dahn a), Harry Guetter a), Arne Henden b),
        Sandra Leggett e), Harold Levison f), Christian Luginbuhl a),
        Joan Martini a), Alice Monet a), Jeffrey Pier a),
        Betty Riepe a), Ronald Stone a), Frederick Vrba a),
        Richard Walker a)

a) U.S. Naval Observatory Flagstaff Station (USNOFS)
b) Universities Space Research Association (USRA) stationed at USNOFS
c) Palomar Observatory, California Institute of Technology
d) USNOFS, now retired
e) USRA, now at University of Hawaii
f) USRA, now at Planetary Science Institute, Boulder CO

============== Abstract =======================

    USNO-A is a catalog of 488,006,860 sources whose positions
    can be used for astrometric references.  These sources were
    detected by the Precision Measuring Machine (PMM) built and
    operated by the U. S. Naval Observatory Flagstaff Station
    during the scanning and processing of the Palomar Observatory
    Sky Survey I (POSS-I) O and E plates, the UK Science Research
    Council SRC-J survey plates, and the European Southern
    Observatory ESO-R survey plates.  The PMM detects and processes
    at and beyond the nominal limiting magnitude of these surveys,
    but the large number of spurious detections requires that a
    filter be used to eliminate as many as possible.  USNO-A's
    sole inclusion requirement was that there be spatially
    coincident detections (within a 2 arcsecond radius aperture)
    on the blue and red survey plate.  For field centers of -30
    degrees and above, data come from POSS-I plates, while data
    from field centers of -35 and below come from SRC-J and ESO-R

    USNO-A presents right ascension and south polar distance in
    the system of J2000 at the epoch of the survey blue plate
    for each object, and lists an estimate of the blue and
    red magnitude.  For POSS-I sources, the photometric system is
    the photographic system defined by the O and E emulsions and
    filters, while southern sources are measured in the photometric
    system defined by the IIIa-J and IIIa-F emulsions.  It is believed
    that the typical astrometric error is about 0.25 arcseconds and
    that the typical photometric error is about 0.25 magnitudes.
    However, these error estimates are dominated by the systematic
    errors incorporated in the calibration procedure, and some
    fields may be significantly worse.  Should users be willing to
    locally recalibrate the astrometry and photometry, the errors
    arising from the PMM are believed to be in the range of 0.15
    arcsecond and 0.15 magnitude.

    To avoid the necessity of consulting many catalogs, objects
    brighter than 11th magnitude that appear in the Guide Star
    Catalog that were not detected by the PMM were inserted.
    USNO-A covers the entire sky, and goes as deep as O=21, E=20,
    J=22, and F=21 for objects with appropriate colors.  The limiting
    magnitude is brighter for objects with extreme colors, and follows
    from the requirement for a detection on both the blue and red
    survey plate.  Although it covers the entire sky, there are holes
    in the catalog in the vicinity of bright stars, regions of nebulosity,
    crowded fields, etc.

============== Statement of Intellectual Property Rights ====================

   This catalog contains data from a diverse collection of photographs,
reductions, and catalogs.  A large number of different organizations claim
copyright and/or intellectual property rights on the various components.
Although the details differ, all permissions for usage of data are
contingent on unrestricted access.  Distribution and/or other direct costs
can be recovered, but re-packaging, re-formatting, or similar activities,
especially for commercial purposes, are not permitted except as authorized
by the U. S. Naval Observatory in consultation with the other institutions
listed below and as appropriate.

   1) Palomar Observatory, National Geographic Society, and California
      Institute of Technology own Palomar Observatory Sky Surveys I and II.

   2) European Southern Observatory owns the ESO-R survey.

   3) The UK Particle Physics and Astronomy Research Council (formerly
      Science and Engineering Research Council and before that Science
      Research Council) owns the SRC-J survey.

   4) Space Telescope Science Institute (and AURA and NASA) own the
      Guide Star Catalog.

   5) US Naval Observatory owns the digitization of the plates and the
      object parameters and catalogs made from them.

   6) The Anglo-Australian Telescope Board retains the copyright to plates
      taken with the U.K. Schmidt Telescope after 15 June 1988.

In particular, we reserve the rights to compile and distribute zone catalogs,
summary catalogs, or other significant pieces of USNO-A beyond that which is
needed to support personal or institutional scientific or educational projects.
Included in this is the preparation and distribution of images generated
from the USNO-A catalog beyond those needed for finding charts and similar
purposes.  In summary, you are welcome to use the catalog, but significant
redistribution, extraction, and image rights are reserved, and permission
needs to be obtained before using this catalog for such purposes.

Please don't make us wake up the lawyers.  Please treat these data and
catalogs in the spirit in which they were created.  They are for non-profit
educational and scientific pursuits, and not for third parties to remarket
for a profit.

=======================Request for Citations=================================

It is an unfortunate aspect of modern funding that impersonal and statistical
measures are used to assess the productivity and usefulness of programs.
If you benefited from using USNO-A, we ask that you give the catalog a
citation.  By doing so, we may be able to justify the expense of continued
production of catalogs.  Whenever possible, it would be appropriate to note
which survey (POSS-I, ESO, and/or SRC) supplied the relevant data, since
these surveys are measured, in part, by the extent to which they serve the

=======================How To Proceed====================================

There is no paper copy of this catalog.  All documentation that exists
has been put somewhere on the CD-ROM set.  A reasonable strategy for
learning about and using this catalog is the following. - Contains a brief description and the necessary statement
             of intellectual property rights.

   read.use - Contains a description of the format of the various files
              and what they contain.  A companion file, demo.tar, contains
              the source code for a simple program that uses this catalog.

   catalog.tar - contains the ASCII text files that describe each of the
                 plates taken as part of the various surveys.  Of particular
                 interest is the epoch of each plate since proper motions
                 have not been computed and applied to the position of
                 each source.

   read.ast - Contains a description of the astrometric reduction procedure.

   read.pht - Contains a description of the photometric reduction procedure.

   read.pmm - Contains a description of the PMM hardware and software.

   sg1.tar - Contains the source code for all software needed to run the
             PMM and do the real time processing.  Included in this file
             are the bias and flat field frames as well as the coefficients
             used in the geometric calibration procedure.

   binary.tar - Contains the source code for about half of the routines
                used to reduce the raw PMM data and produce this catalog.

   newbin.tar - Contains the source code for the rest of the routines
                used to reduce the raw PMM data and produce this catalog.

================Table of Contents=====================

       File                  CD-ROM

   zone0000.acc/.cat            1
   zone0075.acc/.cat            1
   zone0150.acc/.cat            6
   zone0225.acc/.cat            5
   zone0300.acc/.cat            3
   zone0375.acc/.cat            2
   zone0450.acc/.cat            1
   zone0525.acc/.cat            4
   zone0600.acc/.cat            6
   zone0675.acc/.cat            5
   zone0750.acc/.cat            7
   zone0825.acc/.cat           10
   zone0900.acc/.cat            8
   zone0975.acc/.cat            7
   zone1050.acc/.cat            8
   zone1125.acc/.cat            9
   zone1200.acc/.cat            9
   zone1275.acc/.cat            4
   zone1350.acc/.cat           10
   zone1425.acc/.cat            3
   zone1500.acc/.cat            2
   zone1575.acc/.cat            6
   zone1650.acc/.cat            2
   zone1725.acc/.cat            3

   .lut files for all zones     7
   pmmgsc.len                   7                      1
   read.ast                     1
   read.pht                     1
   read.pmm                     1
   read.use                     1

   demo.tar                     1
   catalog.tar                  2
   newbin.tar                   6
   binary.tar                   8
   sg1.tar                      8

================Other Notices=====================

The source codes are the intellectual property of the U. S. Naval
Observatory and are provided so that the expert user can answer detailed
questions about how the catalog was constructed.  Casual users should
avoid them because they contain no instructions as to where various useful
things are hidden.  Release of the source code is made to support such
investigations only, and is not intended for commercial or other
non-professional applications.  The source code is a protected property,
and illegal usage is prohibited.  If in doubt, please contact Dave Monet
for clarifications and protections.

The PMM program has been supported through internal funding by USNO, and
by funding provided by the U. S. Air Force through the Space Surveillance
Network Improvement Program.

This work is based partly on photographic plates obtained at the Palomar
Observatory 48-inch Oschin Telescope for the First and Second Palomar
Observatory Sky Surveys which was funded by the Eastman Kodak
Company, the National Geographic Society, the Samuel Oschin
Foundation, the Alfred Sloan Foundation, the National Science
Foundation grants AST84-08225, AST87-19465, AST90-23115 and
AST93-18984,  and the National Aeronautics and Space Administration
grants NGL 05002140 and NAGW 1710.

This catalog is based, in part, upon original material from the UK Schmidt
Telescope, copyright in which is owned by the UK Particle Physics and Astronomy
Research Council.  No charge beyond recovery of costs has been made by
USNO or PPARC for the provision of these data.  These data are provided
to its recipient for its purpose without restriction, except on the condition
that the data should not be replicated, in whole or in part, and passed
on for profit.  The plates for the SRC-J survey were taken with the
UK Schmidt Telescope (UKST).

The copyright inherent in the plate material obtained with the UK Schmidt
Telescope taken after 15 June, 1988 rests with the Anglo-Australian
Telescope Board.

The European Southern Observatory holds the copyright to the ESO-R
Survey plate material, and USNO scanned these plates under an agreement
with ESO.  This agreement states, in part, that the data derived from these
scans shall be available to the public without restriction and without
charge beyond recovery of the cost of distribution.

USNO would like to thank NOAO/KPNO for the permission to borrow the glass
copies of the SRC and ESO surveys for scanning, and to Bill Schoening and
Richard Green for their assistance.
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