10/30/2017 – Ephemeris – Halloween preview: The Ghoul Star

Ephemeris for Monday, October 30th. The Sun will rise at 8:17. It’ll be up for 10 hours and 15 minutes, setting at 6:33. The Moon, 3 days past first quarter, will set at 3:50 tomorrow morning.

Tomorrow night is the spookiest night of the year, so lets preview the spookiest star of all. It’s Algol, from Ghoul Star or Demon Star. The Chinese had a name for it that meant ‘piled up corpses’. It’s the second brightest star in the constellation Perseus the hero, rising in the northeast this evening. The star is located where artists have drawn the severed head of Medusa, whom he had slain. Medusa was so ugly that she turned all who gazed upon her to stone. Algol is her still glittering eye. Astronomers finally found out what was wrong with Algol. It does a slow 6 hour wink every two days 21 hours, because it is two stars that eclipse each other. It began to dip this morning just before sunrise and it will again centered on 11:41 p.m. Friday night.

The times given are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Perseus, Cassiopeia, Andromeda with Algol finder animation for Autumn evenings. Created using Stellarium and GIMP.

Animation of an eclipsing binary star like Algol. Credit: Wikimedia Commons h/t Earth and Sky