dipper@utastro.UUCP (Debbie Byrd) (11/18/84)
One star in the heavens is named the Ghoul Star. More on how Algol got its name -- right after this. November 18 How the Ghoul Star Got Its Name In the constellation Perseus there's a star named Algol -- one of the most famous stars in the sky. The reason is that it's a naked-eye variable star -- you can see it go up and down in brightness. Algol varies with clocklike regularity. It reaches minimum brightness every two days, twenty hours, twenty-nine minutes and eight seconds. The reason it varies is that it's a double star, with a companion that orbits around it more or less in our line of sight. When the the companion wheels in front of Algol, an eclipse of the main star occurs, and the light reaching us from Algol appears dimmer than it was -- for about ten hours. Algol was named by early Arabian stargazer. Its name means the Demon or Ghoul Star. You might imagine that the Arabs saw Algol blinking -- and that they associated it with a ghoulish monster, which peered down from the heavens, and blinked slowly while eying its prey. The Arabs knew Algol and named it -- but the detailed origin of the name is lost in prehistory. OUR constellation tradition has come down through the Greeks, who named Algol for the monster Medusa, a sort of witch who had snakes instead of hair. In Greek mythology, Medusa was killed by Perseus -- now the home constellation of the variable star Algol. Strangely enough, scientists didn't observe Algol's blinking until 1660, when an Italian professor of mathematics took the name seriously -- and watched the star carefully for several years. Script by Deborah Byrd (c) Copyright 1983, 1984 McDonald Observatory, University of Texas at Austin