dipper@utastro.UUCP (Debbie Byrd) (04/24/85)
The maverick planet Pluto is now opposite the sun from Earth -- and doing something very exciting. More -- after this. April 23 Pluto's Opposition Today Pluto is at opposition -- opposite the sun as seen from Earth, Pluto rises when the sun sets and is visible through telescopes all night long. Pluto's opposition this year is especially exciting -- because this world and its moon have begun a long-awaited series of eclipses of each other. Pluto's moon was discovered in 1978. Astronomers have believed in its existence -- though the best evidence was just a photographic image of Pluto with a bump on one side. The bump is the moon, which has been called Charon. The moon is so close to Pluto, so small, and so far away that it's hard to see. But, even though we can't see it very well, Pluto's moon has promised to reveal a great deal. Astronomers predicted that Pluto and Charon would begin eclipsing each other seen from our vantagepoint in space -- sometime after 1982. It's been a long wait -- but the eclipses have finally begun. The first definite eclipse of Pluto and Charon was detected this past February 17 right here at McDonald Observatory -- and confirmed three days later by astronomers in Hawaii. The eclipses prove without a doubt that Pluto's moon exists! But the upcoming series of eclipses, which should last for several years, will help us learn about the only worlds in the solar system NOT scheduled for an encounter with a spacecraft in this century. By observing the eclipses, we'll learn about the sizes, shapes, and densities of Pluto and its moon -- and also about the geographies of dark and light areas on the surfaces of these dim and distant worlds. Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin