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Posts Tagged ‘Ghoul Star’

10/28/2021 – Ephemeris – The spookiest star in the sky

October 28, 2021 Comments off

This is Ephemeris for Thursday, October 28th. Today the Sun will be up for 10 hours and 21 minutes, setting at 6:36, and it will rise tomorrow at 8:17. The Moon, at last quarter today, will rise at 12:31 tomorrow morning.

We are getting down to the spookiest time of the year, with Halloween on Sunday, so it’s time to talk about the spookiest star in the sky, Algol the Ghoul or Demon Star. It’s in the constellation of Perseus the hero, now rising in the northeastern sky. The constellation itself looks like the Greek letter pi, or like the cartoon Roadrunner with its long legs. Algol is the second brightest star in the constellation, near the Roadrunner’s leading foot. That’s where the eye of the severed head of Medusa, that Perseus is carrying. It’s still winking, once every 2 days and 21 hours*. Tonight it will be in the deepest part of its wink at 8:43 pm. It will take about three hours to recover its usual brightness. I recall that the ancient Chinese weren’t fond of that star either.

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.

* More specifically, 2 days, 20 hours, 49 minutes on average and altered by Earth’s changing distance from the star due to its orbit of the Sun.

Addendum

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.

Algol is an eclipsing binary star, where one star eclipses the other.

Eclipsing Binary Star

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

10/30/2020 – Ephemeris – The spookiest star in the sky

October 30, 2020 Comments off

This is Ephemeris for Friday, October 30th. Today the Sun will be up for 10 hours and 14 minutes, setting at 6:33, and it will rise tomorrow at 8:20. The Moon, 1 day before full, will set at 8:08 tomorrow morning.

With the COVID virus around probably the only spooky thing out tomorrow night will be the star Algol. It’s out every night actually. It’s name, Algol, is from the Arabic for Ghoul Star or Demon Star. The Chinese had a name for it that meant “piled up corpses”. 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 winking eye. The star got the name 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 at its dimmest at 12:11 am November 13th. Remember, daylight time ends on Sunday.

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

Addendum

Algol at 7:30 p.m. on Halloween

Algol at 7:30 p.m. on Halloween, in a modern portrayal. Created using Stellarium.

Eclipsing Binary Star

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

Algol minima table

Algol Minima through November 24th 2020. Click on the image to enlarge. Eclipses are about 10 hours long with 5 hours of dimming and another 5 hours to regain brightness. Source: Insula Astra http://www.astropical.space/algol.php.

 

 

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

October 30, 2017 1 comment

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

Algol Finder

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

Eclipsing Binary Star

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

 

10/31/2016 – Ephemeris – What’s a Halloween sky without the Ghoul Star

October 31, 2016 Comments off

Ephemeris for Halloween, Monday, October 31st.  The Sun will rise at 8:20.  It’ll be up for 10 hours and 12 minutes, setting at 6:32.  The Moon, 1 day past new, will set at 7:28 this evening.

Not all the ghosts and goblins out tonight will be children.  One is out every night, because it’s a star.  Its name is Algol, from the Arabic for 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 2 days 21 hours because it is two very close stars that eclipse each other in that period.  It did so this morning at 5:53 a.m.

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

Addendum

To run an app to calculate times for the minima of Algol click here:  http://www.skyandtelescope.com/observing/celestial-objects-to-watch/the-minima-of-algol/ courtesy of Sky and Telescope Magazine.

Perseus with Cassiopeia and Andromeda in the northeast at 9 p.m. October 20, 2016. Created using Stellarium and GIMP

Perseus with Cassiopeia and Andromeda in the northeast at 8:30 p.m. on Halloween.  Created using Stellarium and GIMP.

Eclipsing Binary Star

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

 

 

 

10/31/2012 – Epmeneris – The Ghoul Star

October 31, 2012 Comments off

Ephemeris for Halloween, Wednesday, October 31st.  The sun will rise at 8:19.  It’ll be up for 10 hours and 12 minutes, setting at 6:32.   The moon, 2 days past full, will rise at 7:37 this evening.

Not all the ghosts and goblins out tonight 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.  The Chinese had a name for it that meant a mausoleum or more ominously ‘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 very close stars that eclipse each other in that period.

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

Addendum

The constellation Perseus in the northeast at 10 p.m. on October 18, 2012. Created using Stellarium.

The constellation Perseus in the northeast at 9 p.m. on October 31, 2012. Created using Stellarium.

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. Image found with the article on Algol in Wikipedia.

Note that this is a mirror image.  The star charts in the 17th century were based on celestial globes, which represented the constellations as seen from the outside of the celestial sphere instead of from the inside.  I reversed the image to match Perseus as we see him.