The Sky This Week, 2012 April 24 - May 1
Mars, 2012 April 14, 02:48 UT
Saturn, 2012 April 14, 04:23 UT
The Moon waxes in the evening sky this week. She starts off close to the bright planet Venus on the evening of the 24th and ends April in the company of ruddy Mars. First Quarter occurs on the 29th at 5:57 am Eastern Daylight Time. This is perhaps the best time of the year to examine Luna’s surface through a small telescope. As she waxes to First Quarter she travels along the northern extremes of the ecliptic, so we can view her growing phases while she is high in the western and southern sky with minimal interference from earth’s atmosphere.
The Moon, Venus, Mars, Saturn, and a host of other celestial objects will be targets of many telescopes that will be deployed by amateur astronomers throughout the region on the evening of the 28th. That night is the culmination of Astronomy Day activities that will be celebrated around the world as the concluding event in Global Astronomy Month. Here in the Washington, DC area the largest Astronomy Day event will be hosted by the Northern Virginia Astronomy Club at Sky Meadows State Park near Paris, Virginia. Programs begin at 3:00 pm with activities and talks, followed by several hours of telescope observing sponsored by club members. While there is a small entrance fee to get into the park, all the activities are free and family-oriented. If you have ever wondered about amateur astronomy and all that it has to offer this is an excellent way to gain a great introduction. If you can’t make it to Sky Meadows, several other astronomy clubs in the area will also be holding their own programs.
Besides the Moon, the brightest attraction in the sky right now is Venus. The best evening elongations of this dazzling planet occur at eight year intervals for Northern Hemisphere observers, and this is one of those favorable years. If you had to choose the best time to look at Venus in all her glory, this would probably be the best week. She reaches her greatest brilliancy at a searing magnitude -4.7 on the 30th, when she sets at around 11:30 pm. She ends April on a dazzling high note, but as May progresses she rapidly drops from the evening sky. The current evening apparition will end dramatically on June 5th, when Venus passes directly between the Earth and the Sun. Venus will transit the solar disc on that day in an event that won’t occur again until December of 2117. Through the telescope Venus sports a fat crescent disc that will grow in diameter and shrink in phase as conjunction draws closer.
If you’re out and looking west shortly after sunset you might still be able to catch a fleeting glimpse of Jupiter just above the western horizon. He is now only visible during evening twilight, and by the week’s end he sets only 45 minutes after the Sun.
Ruddy Mars is on the meridian as twilight ends, high in the southern sky. He’s just under five degrees to the east of the bright star Regulus in Leo, and the gap between the two objects will slowly widen as the red planet resumes direct eastward motion against the stars. Through the telescope Mars’ shrinking disc is now showing a distinct gibbous phase. Modest telescopes of six or more inches aperture will still show some details on his ruddy surface for those observers with a patient eye and steady air. Mars receives a visit from the waxing gibbous Moon on the evening of the 30th.
Saturn is now the planet with the biggest "Wow" factor for telescopic viewers. To the naked eye he’s neither dazzling nor particularly colorful, although his yellowish cast contrasts with the pale blue of the nearby bright star Spica, lead star of the constellation Virgo. Both objects climb into the southeastern sky after the end of evening twilight, and by 10:00 pm Saturn is ready for viewing through the telescope. If there is one object other than the Moon that gets everyone’s attention at the eyepiece, it is Saturn. Even after decades of looking at the ringed planet through telescopes of all sizes I still get a thrill whenever I observe him through any instrument.