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11/24/2016 – Ephemeris – The little constellation that used to start the seasonal year
Ephemeris for Thanksgiving Day, Thursday, November 24th. The Sun will rise at 7:52. It’ll be up for 9 hours and 14 minutes, setting at 5:06. The Moon, 3 days past last quarter, will rise at 3:54 tomorrow morning.
From antiquity, the first constellation of the Zodiac has been Aries the ram. That’s the constellation the Sun entered on the first day of spring, or the vernal equinox. Well that was a couple of thousand years ago. Currently the vernal equinox point is in western Pisces. This is due to the wobbling of the Earth’s axis called precession. The spinning Earth like and top or gyroscope wobbles when force is applied to it. In this case the Sun and Moon. One wobble takes 26,000 years to complete. Anyway, Aries is a small constellation of four stars in a bent line, below the triangular constellation of Triangulum, which is itself below Andromeda. It’s a bit west or right of the Pleiades or Seven Sisters star cluster.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Aries the ram animated finder chart for 9 p.m. November 24, 2016. Created using Stellarium and GIMP.
The vernal equinox today, where the blue line, the celestial equator and the orange line, the ecliptic or path of the Sun cross. The Sun is where these lines cross on the first day of spring (March 20th around here). Note that the vernal equinox is now in western Pisces. Created using Stellarium.
The vernal equinox back in AD 100, where the blue line, the celestial equator and the orange line, the ecliptic or path of the Sun cross. The Sun is where these lines cross on the first day of spring. Note that the vernal equinox was at the east edge of Pisces. Created using Stellarium.
10/31/2016 – Ephemeris – What’s a Halloween sky without the Ghoul Star
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 8:30 p.m. on Halloween. Created using Stellarium and GIMP.
Animation of an eclipsing binary star like Algol. Credit: Wikimedia Commons h/t Earth and Sky
10/20/2016 – Ephemeris – Perseus: Is it a hero or a chicken?
Ephemeris for Thursday, October 20th. The Sun will rise at 8:05. It’ll be up for 10 hours and 43 minutes, setting at 6:48. The Moon, 2 days before last quarter, will rise at 10:54 this evening.
Positioned below the W shaped constellation of Cassiopeia half way up the sky in the northeast at 9 p.m. is the constellation of Perseus the hero of Greek myth who slew Medusa and rescued and married Andromeda represented in the constellation above and right of him. Rather than a hero the star pattern seems to look like a chicken or perhaps Big Bird. At least, that’s how I see it. In the back of the chicken is its brightest star Mirfak (Mirphak). Binoculars will show a beautiful group of stars near Mirfak just below unaided eye visibility called the Alpha Persei Association. Tomorrow morning will see the peak of the Orionid meteor shower, though all but the brightest meteors will be overwhelmed by waning gibbous Moon.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Perseus with Cassiopeia and Andromeda in the northeast at 9 p.m. October 20, 2016. Created using Stellarium and GIMP.
10/03/2016 – Ephemeris – Cassiopeia the celestial queen, and a look at Venus with the Moon
Ephemeris for Monday, October 3rd. The Sun will rise at 7:43. It’ll be up for 11 hours and 34 minutes, setting at 7:18. The Moon, 3 days past new, will set at 8:55 this evening.
The stars of autumn are in the northeastern to southeastern part of the evening sky. Look half way up the sky in the northeast at 9 p.m. and you can find the W shaped constellation of Cassiopeia the queen. Cassiopeia never sets for us in Michigan. It is opposite the pole star Polaris from the Big Dipper. Above Cassiopeia is a dim church steeple shaped constellation of Cepheus the king. The steeple is toppled to the left. The Milky Way flows through Cassiopeia and through a corner of Cepheus to the bright star Deneb in Cygnus the Swan, or Northern Cross, overhead. Below Cassiopeia it flows through the constellation of Perseus the hero, which kind of looks like a chicken, to the bright star Capella near the horizon.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The crescent Moon will appear above Venus tonight.
Looking very low in the west-southwest at 7:38 p.m., 20 minutes after sunset, October 3, 2016. The thin crescent Moon will appear about 4 degrees 15 minutes (8 1/2 moon diameters) above Venus. Created using Stellarium.
Cassiopeia with Cepheus, Cygnus and Perseus in the Milky Way in the northeastern sky. Created using Stellarium.
09/27/2016 – Ephemeris – The princess Pegasus helped save
Ephemeris for Tuesday, September 27th. The Sun will rise at 7:36. It’ll be up for 11 hours and 53 minutes, setting at 7:29. The Moon, 3 days before new, will rise at 5:08 tomorrow morning.
In the east at 9 this evening can be found a large square of stars standing on one corner, the Great Square of Pegasus the flying horse. What look like its hind legs stretching to the left from the left corner star is another constellation, Andromeda the chained princess. She is seen in the sky as two diverging upward curving strings of three stars each. She was rescued by the hero Perseus, a nearby constellation, riding Pegasus. Andromeda’s claim to astronomical fame is the large galaxy seen with the unaided eye just above the upper line of stars, the Great Andromeda Galaxy, 2.5 million light years away. To the unaided eye the galaxy appears as a small smudge of light. In binoculars the galaxy is a delicate spindle of light.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Andromeda, Pegasus and Perseus in the east. Created using Stellarium.
I added some constellation lines to Andromeda since yesterday to match the transcript and how I see her. Looks like I have some work to do with Perseus, before I talk about him later on. He doesn’t look like a chicken enough. I’m going for laughs here.
Andromeda. Pegasus and Perseus in the east. Created using Stellarium, art by Johan Meuris.
10/30/2015 – Ephemeris – The spookiest star
Ephemeris for Friday, October 30th. The Sun will rise at 8:17. It’ll be up for 10 hours and 16 minutes, setting at 6:34. The Moon, 3 days past full, will rise at 9:33 this evening.
Tomorrow night is the spookiest night of the year, so lets look at 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 winked this morning and it will again centered on 11:45 p.m. Sunday night.
Times 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, in a modern portrayal. Created using Stellarium.
Animation of an eclipsing binary star like Algol. Credit: Wikimedia Commons h/t Earth and Sky
11/28/2014 – Ephemeris – Not quite a star cluster, but pretty cool nonetheless
Ephemeris for Friday, November 28th. The sun will rise at 7:55. It’ll be up for 9 hours and 9 minutes, setting at 5:04. The moon, 1 day before first quarter, will set at 12:01 tomorrow morning.
When is a star cluster not a star cluster? When it’s an association. That is when it has begun to dissipate because the gravitational force of the group cannot hold it together. The central stars of the Big Dipper belong to The Ursa Major Association. Below the W shaped constellation of Cassiopeia in the northeast at 9 or 10 p.m. Is the constellation of Perseus (Per-seus or Pers-e-us) as it is usually pronounced. Its brightest star is Mirfak with a designation of Alpha Persei. There are some stars there to the naked eye, but with binoculars there are a great many stars just below naked eye visibility. This is called the Alpha Persei association. It is perfect to spot with binoculars, but way too wide-spread for a telescope.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
The Constellations Cassiopeia, Perseus and Auriga. Cartes du Ciel
Alpha Persei Association. Created using Stellarium.
10/31/2014 – Ephemeris – The spookiest star
Ephemeris for Halloween, Friday, October 31st. The sun will rise at 8:18. It’ll be up for 10 hours and 13 minutes, setting at 6:32. The moon, 1 day past first quarter, will set at 1:59 tomorrow morning.
Not all the ghosts and goblins out Sunday 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 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. Her next wink will be 10 p.m. Sunday night.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Perseus and the head of Medusa from the 1690 Uranographia by Johannes Hevelius. Image found with the article on Algol in Wikipedia.
Celestial globes of the day showed the celestial sphere from the outside, so the constellations appeared reversed. The star atlases of the day kept the trend. I reversed the image to correspond with the actual sky.
Algol at 7:30 p.m. on Halloween, in a modern portrayal. Created using Stellarium.
Update
Animation of an eclipsing binary star like Algol. Credit: Wikimedia Commons. H/T EarthSky
Here’s a link to EarthSky’s post on Algol.
10/28/2013 – Ephemeris – The constellation Perseus the hero
Ephemeris for Monday, October 28th. The sun will rise at 8:15. It’ll be up for 10 hours and 21 minutes, setting at 6:36. The moon, 2 days past last quarter, will rise at 2:54 tomorrow morning.
About a third the way from the east northeastern horizon to the zenith at 9 p.m. and below the letter W shaped constellation of Cassiopeia the queen is Perseus the hero. It’s kind of a odd shape for a hero, To me it looks like a chicken running across the road. To those who’s imagination doesn’t run to poultry, its shape is also like the Greek letter pi. It’s two brightest stars are Mirfak and Algol the demon star. Look at the area around Mirfak with binoculars and you will see a large group of stars just below naked eye visibility. It’s called the Alpha Persei association. That because Mirfak is Alpha Persei. The group is about 560 light years away, which means, though close, are farther away than the Pleiades, below and right of them.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Perseus finder chart. Note the star Mirfak is spelled Mirphak on the chart. Created using Stellarium.
Alpha Persei Association. Created using Stellarium.
Perseus and the head of Medusa from the 1690 Uranographia by Johannes Hevelius. Image found with the article on Algol in Wikipedia.
09/03/2013 – Ephemeris – The constellation of Pegasus the flying horse
Ephemeris for Tuesday, September 3rd. The sun will rise at 7:07. It’ll be up for 13 hours and 7 minutes, setting at 8:14. The moon, 2 days before new, will rise at 6:20 tomorrow morning.
A reminder that the end of summer is approaching is located in the east around 10 p.m. It’s one of the great autumn constellations: Pegasus the flying horse of Greek myth. Its most visible feature is a large square of four stars, now standing on one corner. This feature, called the Great Square of Pegasus, represents the front part of the horse’s body. The horse is quite aerobatic, because it is seen flying upside down. Remembering that fact, the neck and head is a bent line of stars emanating from the right corner star of the square. Its front legs can be seen in a gallop extending to the upper right from the top star of the square. In Mythology Pegasus was born of the blood of Medusa, decapitated by the hero Perseus, seen as a constellation rising in the northeast.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.
Addendum
Pegasus image in the stars at 10 p.m. September 3, 2013. Created using Stellarium. Drawing by Johan Meuris.
Bob Moler's Ephemeris Blog 