Spectacular predawn gathering of Moon and planets Sunday, July 15, 2012

EAST LANSING -- You wonít want to miss Sunday's spectacular predawn compact gathering of the three brightest night sky objects, the Moon, Venus, and Jupiter. You can get up early to observe the celestial gathering on your own, or join a former MSU astronomer on the top level of the parking ramp immediately behind Abrams Planetarium on the campus of Michigan State University.

The session will be held atop the west end of the parking ramp immediately behind the Planetarium from 4:30 a.m. until 5:15 a.m. Stairways in the northwest or southwest corner of the parking ramp, or the elevator in the southwest corner, can be used for easy access to the top level.

The gathering of objects will appear low in the east-northeast sky as twilight begins to brighten, about one and three quarters hours before sunrise. What will seem to be the brightest "star" in the grouping, about 4 degrees lower right of the Moon, will actually be the planet Venus. The next brightest "star", within 7 degrees above Venus, is also a planet, Jupiter. Within 3 degrees to Venus' upper right is the star Aldebaran, marking the eye of Taurus, the Bull. The views through binoculars will be exquisite: Several stars in the same field of view as Aldebaran are members of a cluster of stars called the Hyades. Another star cluster, much more compact, is the dipper-shaped Pleiades or Seven Sisters, within 9 degrees above Jupiter on Sunday morning.

Visualize this scene in three dimensions! Venus is close by, at 0.47 a.u., and Jupiter some 12 times farther, at 5.67 a.u. (One astronomical unit, or a.u., is the average distance from Earth to Sun, or about 93 million miles.) Expressed in light travel time, the Moon is only about 1-1/3 light-seconds from Earth, Venus is now about 3.9 light-minutes from Earth, and Jupiter 47 light-minutes. But the stars are much farther away: Aldebaran 67 light-years, the Hyades about 150 light-years, and the Pleiades about 400 light-years.

Telescopes will provide pleasing close-up views of craters on the Moon, Jupiter and its system of four bright moons, and Venus as a crescent, now nearly 30 percent illuminated. (Venus is closer to us than the Sunís 1.0 a.u. and is therefore backlighted by the Sun.) This Sunday morning, the nearby crescent Moon can help you follow Venus until sunrise and for several hours beyond. When viewing Venus with low- power instruments such as binoculars, around sunrise or in the daytime is best, to eliminate its contrast against a dark sky. Mount the binoculars on a sturdy tripod, or hold them steady by resting your elbows on a car roof, and you might resolve the tiny Venus crescent!

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