Jimmy Westlake: Bright planets light morning sky
July 2, 2012
It seems like something is missing from our evening sky. For the first several months of 2012, the dazzling "evening star" Venus dominated our evening sky as soon as the sun went down. Then, Venus treated us Earthlings to a rare transit across the face of the sun in early June. Where has the planet Venus gone?
Early risers already know the answer to that question. Venus has flip-flopped to the other side of the sun and now is the bright "morning star" dominating our pre-dawn sky.
As July begins, Venus and Jupiter are positioned very close to each other against the stars of the constellation Taurus the Bull. The sky's two brightest planets passed closest to each other Sunday, but will remain within 14 degrees of each other throughout the month. Dazzling Venus is the brighter of the two, outshining brilliant Jupiter by a factor of nine.
Seen through a small telescope this month, Venus presents a very pleasing little crescent phase, resembling a tiny version of the moon. Jupiter, through a telescope, shows off its four giant moons: Io, Europa, Ganymede and Callisto.
On the Fourth of July, Venus and Jupiter will align with the bright star Aldebaran and the sparkling Pleiades star cluster, all in a straight line across the multicolored predawn sky.
On the morning of July 9, Venus will shine less than 1 degree from Aldebaran, the star marking the glaring red eye of Taurus the Bull.
Granted, it is tough to get out of bed at 4:30 a.m., so if you only do it one time this month, make that morning July 15. That's the morning that the slender crescent moon joins Venus, Jupiter, Aldebaran and the Pleiades for an unforgettable conjunction. The moon will rise at about 3 a.m. with Venus on one side and Jupiter on the other.
On the afternoon of Aug. 13, the waning crescent moon will eclipse the planet Venus for about an hour beginning at 2:30 p.m. MDT. This is a daytime event and will not be something to watch with the unaided eye, but careful scanning with binoculars should reveal Venus and the moon about 45 degrees (three hand spans at arm's length) to the lower right of the sun. Start scanning before 2:30 p.m. so you can watch Venus blink out as it passes behind the moon. Venus pops out from behind the moon at about 3:38 p.m.
Venus manages to pull a little farther from the sun each morning until Aug. 15, when the planet will reach its greatest elongation, 46 degrees west of the rising sun. On that morning, Venus will rise a full 3 1/2 hours before the sun.
Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College's Alpine Campus. His "Celestial News" column appears weekly in the Steamboat Today newspaper and his "Cosmic Moment" radio spots can be heard on local radio station KFMU. Check out Westlake's astrophotography website at http://www.jwestlake.com.