dipper@utastro.UUCP (Debbie Byrd) (09/10/84)
After sunset Monday or Tuesday, look for the rising full moon. More on the Harvest Moon -- right after this. September 10 The Harvest Moon Every full moon has a name -- which coincides with a month of the year. September's full moon is the Fruit Moon -- but this name is often overlooked -- since in September we generally see the legendary Harvest Moon. The Harvest Moon is the one nearest the autumn equinox -- which comes this year on September 22. The Harvest Moon is said to be unusually big and yellow -- but it isn't really. It's just that this full moon rises on a path that makes a very narrow angle with the horizon -- so the Harvest Moon stays near the horizon longer than most full moons. The rising Harvest Moon isn't bigger or yellower than most full moons -- but several horizon effects may make it look big and yellow for a longer time. The golden color of the rising full moon results from seeing it through a greater thickness of air than when the moon is overhead. But the bigness of the rising full moon results from a trick played by your own eyes and brain. When you next see a full moon rising, place your thumb and forefinger on either side of the moon, as though you're trying to pluck it from the sky. When compared to something nearby, like your fingers, the moon will shrink to its normal size. When you see an extra-large full moon near the horizon, you're seeing what's called "the moon illusion." The moon was exactly full during the wee hours Monday morning. For the next night or two, it'll rise shortly after the sun goes down -- a great ball of golden light. Script by Deborah Byrd. (c) Copyright 1983, 1984 McDonald Observatory, University of Texas at Austin