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Posts Tagged ‘Variable Stars’

10/31/2019 – Ephemeris – The perfect Halloween star

October 31, 2019 Comments off

Ephemeris for Halloween, Thursday, October 31st. 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, half way from new to first quarter, will set at 9:22 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. 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’s next nighttime minimum will be 1:46 a.m. on November 12th.

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

Here is a web sit where you can calculate the minima of Algol and other eclipsing stars:  http://www.astropical.space/algol.php

10/30/2018 – Ephemeris – Algol the spookiest star in the sky

October 30, 2018 Comments off

Ephemeris for Tuesday, October 30th. The Sun will rise at 8:18. It’ll be up for 10 hours and 16 minutes, setting at 6:34. The Moon, 1 day before last quarter, will rise at 11:53 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. 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 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 dimmest at 8:10 p.m. November 13th.

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

10/05/2012 – Ephemeris – Tonight’s astronomical events in Traverse City

October 5, 2012 Comments off

Ephemeris for Wednesday, October 3rd.  The sun will rise at 7:43.  It’ll be up for 11 hours and 35 minutes, setting at 7:18.   The moon, 4 days past full, will rise at 8:59 this evening.

Let’s see how many bright planets we can find this week.  Mars and Saturn now set too close to the sun to be easily seen in the evening sky.  Both are in the west southwestern sky and very low in twilight.  Saturn sets at 8:10 p.m., while Mars sets at 9:08.  The planetary action moves to later in the evening and the morning. Jupiter, will rise at 10:09 p.m. in the east northeast.  It is located in the constellation of Taurus.  The last bright planet of the night is the morning star Venus which will rise at 4:13 a.m. also in the east northeast.  Venus is now in Leo outshining the star Regulus next to it.  The planets Venus and Jupiter and the winter constellations are a great sight for early risers.  You can enjoy them without danger of frost bite.

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

Addendum

Jupiter and the waning gibbous moon at 11 p.m. October 5, 2012.  Created using Stellarium.

Jupiter and the waning gibbous moon at 11 p.m. October 5, 2012. Created using Stellarium.

Jupiter with its moons at 11 p.m. October 5, 2012.  Created using Stellarium.

Jupiter with its moons at 11 p.m. October 5, 2012. Created using Stellarium. Stellarium shows the moons much brighter than they actually appear. compared to Jupiter.