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Ephemeris: 10/30/2023 – Just in time for Halloween – Algol the Demon Star

October 30, 2023 Comments off

This is Ephemeris for Monday, October 30th. Today the Sun will be up for 10 hours and 16 minutes, setting at 6:34, and it will rise tomorrow at 8:19. The Moon, 2 days past full, will rise at 7:29 this evening.

Not all the ghosts and goblins out tomorrow night will be children. One will be out every night because it’s a star. Its name is Algol, from the Arabic for Ghoul Star or Demon Star. It’s normally the second brightest star in the constellation Perseus the hero, visible 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. The star got these names before astronomers found out what was wrong with it. They found out that it does a slow wink every two days, 21 hours. That’s because Algol is two stars that eclipse each other. Her next evening wink will be its dimmest at 10:12 p.m. this Wednesday, November 1st.

The astronomical event times given are for the Traverse City/Interlochen area of Michigan (EDT, UT –4 hours). They may be different for your location.

Addendum

For predictions of the minima of Algol for your time zone and for Universal Time (UT) go here: http://www.astropical.space/algol.php

Algol Finder Animation
Algol Finder Animation for around 8 pm in the later part of October and early November (7 pm after the EST time change on the first Sunday in November). Created using Stellarium and GIMP.
Perseus and the head of Medusa from the 1690 Uranographia by Johannes Hevelius.
Perseus and the head of Medusa from the 1690 Uranographia by Johannes Hevelius. Note that the image is mirror reversed. This mimicked the image on a celestial globe, looking from outside the globe. Note a couple of extra constellations: a small triangle below Triangulum, and Musca the fly. There is a Musca constellation in the southern hemisphere. This image was found with the article on Algol on Wikipedia.
Eclipsing Binary Star
Animation of an eclipsing binary star like Algol. Credit: Wikimedia Commons h/t Earth and Sky.
Categories: Constellations, Ephemeris Program, Mythology, Variable Star Tags: , ,