You are here: Home USNO News, Tours & Events Sky This Week The Sky This Week, 2010 May 4 - 11
The USNO websites,,,,, and are undergoing modernization efforts. The expected completion of the work and return of service is estimated as 30 April 2020. Please submit a requirements form to the USNOPAO if the information you are seeking is not accessible via other means.

The Sky This Week, 2010 May 4 - 11

Rivals in the sky...
Saturn & Titan, 2010 May 1, 03:21 UT 
Imaged from Shoestring Observatory, Alexandria, VA
with a 20-cm (8-inch) f/10 Schmidt-Cassegrain telescope,
2X Barlow lens, and Philips "ToUcam" 740K webcam

The Moon wanes through her crescent phases in the pre-dawn sky this week. Last Quarter occurs on May 6th at 12:15 am Eastern Daylight Time. She spends most of the week drifting through the dim constellations of the autumn sky. Her only bright encounter occurs on the morning of the 9th, when she may be seen about five degrees above bright Jupiter in the gathering twilight.

As Luna drifts into the morning sky we bid a fond farewell to the signature constellation of winter. Orion, the hunter now slips below the western horizon as evening twilight ends, with the ruddy star Betelgeuse the last of his bright stars to set. In mythology the mortal Orion boasted of his hunting prowess, and how there was no animal that he could not overcome. This did not sit well with the goddess Juno, who rightly felt that only she could be endowed with such powers. She therefore sent a lowly scorpion to sting Orion in the heel, causing a mortal wound. Orion, being a favorite of Diana, goddess of the hunt, had Orion placed in the sky as a token of her esteem. Juno, not to be outdone, only allowed such a tribute if she could place the Scorpion in the sky as well. Since those ancient times the two rivals have chased each other around the heavens, but they are never in the sky at the same time. Both constellations have distinctive red-tinted stars among their brightest members, and it is interesting to note that Antares rises a mere 20 minutes before Betelgeuse sets. It is also interesting to note that both constellations are made up of mostly hot blue stars that are among the galaxy’s youngest members. Although they are not physically linked, these two very distinctive star patterns have much in common in both fact and fiction.

Brilliant Venus spends the week gliding toward the gap between the two stars that mark the ends of the "horns" of Taurus, the Bull. By the week’s end she will appear almost exactly between these two stars, and also between setting Betelgeuse and Capella, the brightest star in Auriga, the Charioteer. Venus’ dazzling white glow contrasts nicely with the ruddy hue of Betelgeuse and the golden yellow of Capella.

Mars is now drawing closer to the bright star Regulus, lead star of Leo, the Lion. The red planet has put quite a bit of distance between himself and the Gemini Twins, Castor and Pollux, over the past several weeks. He has also faded considerably and is now barely a first magnitude object, just slightly brighter than Regulus. Through the telescope he is now little more than a small pinkish dot, less than half the apparent size he was at opposition back in January. Mars will linger in the sky for several months, ultimately catching up to and passing Saturn during the summer.

Golden Saturn is now poised under the haunches of Leo, just over 10 degrees south of Denebola, the star that marks the Lion’s tail. Saturn will seem to pause here for the next couple of weeks before he slowly resumes eastward motion back toward the stars of Virgo. The planet’s famous rings now appear as a pair of stilettos poking out from the sides of his disc, but the angle of the Sun causes them to cast a distinct shadow across his equator. He is a very pleasing sight through the telescope right now, so go out on the next clear night and enjoy a look.

Jupiter receives a visit from the waning crescent Moon on the morning of the 9th. The giant planet now rises before the onset of morning twilight and dominates the view to the east as the sky brightens to dawn.

USNO Master Clock Time
Javascript must be Enabled