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The Sky This Week, 2010 May 25 - June 1

More things to look for in the "Near Sky"
ISS_100516_01small.jpg
Trail of the International Space Station
passing between Mars and Regulus,
2010 May 16, 01:37 UT.

15-second exposure with a
Canon PowerShot S2IS digital camera

The Moon remains bright in the evening and early morning sky this week.  Full Moon occurs on the 27th at 7:07 pm Eastern Standard Time.  May’s Full Moon is variously known as the Flower Moon, Corn Planting Moon, Milk Moon, and Hare Moon.  Luna appears to hug the southern horizon as she moves through the rising stars of the summer sky before ending the week among autumn’s dimmer constellations.  On the night of the 27th the Moon glides less than one degree north of the ruddy star Antares as midnight approaches.

Luna’s bright presence in the sky for most of the week means that once again our views of the more subtle stellar phenomena are limited by this natural source of “light pollution”.  Even the disc of the Moon herself becomes almost overwhelmingly bright in the nights on either side of the full phase, and the relief exhibited along the terminator line becomes quite difficult to pick out.  We are thus limited to a handful of sights to enjoy as the nights approach their shortest lengths for the year.  However, as it turns out, this is just about the best time of year to look for artificial earth satellites.  With the final flight of the Shuttle “Atlantis” about to end the International Space Station is now about as large as it’s going to get for the foreseeable future.  This orbiting outpost, almost the size of a football field, can approach Venus in its brightness during very favorable passes, and there are literally dozens of other objects ranging from functional satellites to defunct rocket boosters that silently drift across the skies each night after sunset and each morning before sunrise.  Unfortunately there are no good passes of the ISS over Washington this week, but there is a website where you can check on all of the satellites visible from your back yard on any night of the year.  The Space Station makes favorable passes over most cities in the temperate latitudes for several nights every few weeks.  Check to see the next time it will fly over your way and be sure to wave as it goes by; six people are on board at almost any given time!

The dazzling glow of Venus is still holding sway in the early evening sky.  Best seen during the twilight hours, Venus is now passing through the stars of Gemini in the west-northwestern sky.  She’s closing the gap with the Twin Stars Castor and Pollux, whom she’ll pass in early June.  She’s just keeping pace with the advancing Sun, setting just under 45 minutes after the end of evening twilight for the next couple of weeks.

Ruddy Mars continues to press eastward against the stars.  This week he really shrinks the gap between himself and the bright star Regulus.  He’ll pass by the star in a spectacular close conjunction in the middle of next week.  Mars has faded considerably since his opposition last January.  By the time he passes Regulus he’ll be just a little bit brighter than the star.  The pair will make an attractive sight in binoculars or a low-power telescope by the end of the week when they can be seen in the same field of view; the color contrast between star and planet is quite striking.

Saturn reaches the second stationary point in this year’s apparition on the 31st.  On this date the planet halts his westward retrograde motion and very slowly resumes eastward progress against the stars for the remainder of his time of visibility.  Unlike Mars, Saturn’s progress against the stars is incremental at best.  Both Mars and Venus will catch up to him and pass him by in early August.  His rings, which look more like little spikes in the telescope, are now at their narrowest presentation to the Earth this year.  They will now begin to gradually open up, and by next year’s opposition they’ll look more like their old familiar oval shape.

Jupiter is also plodding eastward against the stars.  The giant planet is pretty much by himself in the star-poor reaches of the constellation Pisces, rising about an hour before the beginning of morning twilight.  Old Jove is still missing his South Equatorial Belt, and more and more telescope owners are also rising before the Sun to catch this very unusual jovian weather event.

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