dipper@utastro.UUCP (Debbie Byrd) (11/08/86)
The moon, Mars and Jupiter Saturday night -- right after this. November 8 The Moon, Mars and Jupiter If you've never identified a planet, look outside tonight, and learn to identify two! The planets Mars and Jupiter are now making a low arc across the south each evening. They start out in the south at sunset -- and set during the middle of the night. Jupiter is always easy to spot, because it's brighter than any star -- brighter than anything else up there with the exception of the moon. And the moon itself can lead you to Mars tonight, even though the red planet is fainter than Jupiter, and relatively inconspicuous. Saturday night, Mars is the closest object to the moon on the dome of our sky. This is a special day for Jupiter because today the planet is stationary -- or poised, temporarily motionless, against the stars. The planets generally move toward the east among the stars -- but at particular times in their orbits they appear to move toward the west. Those times occur for an outer planet, like Jupiter, when Earth passes between it and the sun. Then, as we pull ahead in orbit, we see Jupiter appear to move backwards. Well, Earth passed between Jupiter and the sun in September. And Jupiter has been retrograding, or moving toward the west against the stars, for the past several months. Today it's stationary -- hanging motionless against the starry background of the constellation Aquarius -- and soon it will be moving noticeably eastward again. It won't move fast enough, though, to outrun Mars. Mars is now moving eastward, too. Next month it will catch up to Jupiter -- and pass very near it on the dome of the sky. If you start watching now, you'll see these two worlds draw closer and closer together. Script by Deborah Byrd. (c) Copyright 1985, 1986 McDonald Observatory, University of Texas at Austin