dipper@utastro.UUCP (Debbie Byrd) (03/21/86)
Moonlight will soon obstruct our view of Comet Halley. More -- after this. March 21 Halley and Moonlight Right now is a good time to be looking for Comet Halley. For many of us in the northern hemisphere Saturday morning is the last time we'll get a really good glimpse of the tail of the comet. The moon is just a few days from full -- and soon will be flooding the sky all night long with moonlight -- submerging the light of the comet's tail. If you want to see the comet, plan on getting up several hours before sunrise. As always -- the best view is from a dark location -- and binoculars will be helpful. Now the comet is in the southeast. In a dark enough sky you'll see the comet's tail -- fragile filaments trailing away from the brighter head of the comet. If you look carefully, you may even notice some stars shining dimly through the tail. The tail precedes the comet's head as Halley journeys outward from the sun. The tail is composed of tiny particles of dust and gas that are reflecting light from the sun. The pressure of sunlight pushes on the minute dust particles as they stream away from the coma, and the solar wind -- a fast-moving stream of gas atoms boiled off the sun's outer atmosphere -- pushes on the comet's gas. Comet Halley's tail changes its appearance from day to day. That's partly because the comet irregularly erupts more material, and partly because the gas tail is affected by rapid changes in the magnetic fields carried by the solar wind. After tomorrow moonlight interferes with our view of the comet. So Saturday morning you may want to make a special effort to get out in the country -- for a look at Comet Halley. Don't forget your binoculars. Script by Diana Hadley. (c) Copyright 1985, 1986 McDonald Observatory, University of Texas at Austin