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Posts Tagged ‘Castor’

07/14/2017 – Ephemeris – Constellations of the Summer Triangle II: Cygnus the swan

July 14, 2017 1 comment

Ephemeris for Friday, July 14th. Today the Sun will be up for 15 hours and 14 minutes, setting at 9:25, and it will rise tomorrow at 6:11. The Moon, 2 days before last quarter, will rise at 12:32 tomorrow morning.

Fairly high in the east at 11 p.m. Is the constellation of Cygnus the swan, flying south through the Milky Way. It is also called the Northern Cross. At the left, the tail of the swan or the head of the cross is the bright star Deneb, one of the stars of the Summer Triangle. The next star right is Sadr the intersection of the body and the wings of the swan seen in flight, or the intersection of the two pieces of the cross. There are two or three stars farther to the right that delineate the swan’s long neck or upright of the cross, that ends with the star Alberio in the beak of the swan or foot of the cross. The crosspiece of the cross extends to the stars on either side of the intersection star Sadr, while the swan’s wings extend to a couple more stars each.

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

Addendum

The Summer Triangle July 5, 2012 at 11 p.m. Created using Stellaruim and The Gimp.

The Summer Triangle. Created using Stellarium and The Gimp.

Cygnus finder animation

Animated Cygnus finder chart. Created using Stellarium.

In mythology Cygnus was the form Zeus took in the Leda and the swan affair.  Out of that union was born Pollux of Gemini fame.  His half-brother and twin Castor was fathered by a mere mortal.  Go here for their story.

Alberio is the star that shows in Cygnus’ eye.  In telescopes of even low power Alberio shows as a binary star whose components are distinctly and beautiful blue and gold.  Binoculars are not quite powerful enough to split these two.

01/27/2017 – Ephemeris – The celestial twins

January 27, 2017 Comments off

Ephemeris for Friday, January 27th.  The Sun will rise at 8:06.  It’ll be up for 9 hours and 38 minutes, setting at 5:44.  The Moon is new today, and won’t be visible.

The constellation Gemini, the Twins is visible high in the southeast at 9 p.m.  The namesake stars of the two lads, will be high on the upper left edge of the constellation, nearly vertically aligned.  Castor is above, while Pollux, a slightly brighter star is below it.  Lines of stars from Castor and Pollux to the lower right delineate the lads.  In Greek mythology Castor and Pollux were twins, and half brothers, Castor was fathered by a mere mortal, while Pollux was fathered by Zeus in the famous Leda and the swan affair.  The brothers, however were inseparable, and when Castor was killed during the quest for the Golden Fleece, Pollux pleaded with Zeus to let him die also.  Zeus granted his wish, so both appear in the sky together forever.

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

Addendum

Gemini

Gemini revealed by animation. Created using Stellarium and GIMP.

02/18/2016 – Ephemeris – Castor and Pollux

February 18, 2016 Comments off

Ephemeris for Thursday, February 18th.  The Sun will rise at 7:39.  It’ll be up for 10 hours and 35 minutes, setting at 6:14.   The Moon, 3 days past first quarter, will set at 5:28 tomorrow morning.

The star Pollux is at the head of the same named brother of Gemini the twins.  Castor is the  slightly dimmer star right above it.  Pollux is about 34 light years away.  It’s twice as massive as the Sun, and has run out of hydrogen in its core and is in the process of evolving into a red giant star.  One planet, twice as massive as Jupiter has been detected around it.  Castor is at 51 light years away.  There are 6 stars in its system.  The brightest three are visible in telescopes.  Each is a spectroscopic binary, meaning that the companion stars are detected by the Doppler shifts of the lines in their spectra as the stars orbit each other.   The Doppler shift is just one of the many pieces of information revealed by the spectroscope.

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

Addendum

Castor and Pollux

Castro and Pollux with the bright Moon and other bright stars and constellations of winter. 9 p.m. February 18, 2016. Created using Stellarium.

Castor star system

The Castor star system exploded in this JPL/NASA infographic.

The entire infographic is here.

Categories: Ephemeris Program, stars Tags: , ,

01/11/2016 – Ephemeris – Gemini, the half-brothers that are twins

January 11, 2016 Comments off

Ephemeris for Monday, January 11th.  The Sun will rise at 8:18.  It’ll be up for 9 hours and 4 minutes, setting at 5:22.   The Moon, 2 days past new, will set at 7:36 this evening.

Before the Moon brightens the evening sky, lets look at another of the winter constellations.  The constellation Gemini, the Twins is visible high in the east-southeast, above and left of Orion the hunter at 9 p.m.  The namesake stars of the two lads, will be at the left end of Gemini, vertically aligned.  Castor is on top, while Pollux is below.  From them come two lines of stars extending toward Orion that outline the two.  In Greek mythology the lads were half brothers, Castor was fathered by a mere mortal, while Pollux was fathered by Zeus in the famous Leda and the swan affair, but were born together.  When Castor was killed during the quest for the Golden Fleece, Pollux pleaded with Zeus to let him die also, so both appear together in the sky forever.

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

Addendum

Gemini

Gemini revealed by animation. Created using Stellarium and GIMP.

12/15/2015 – Ephemeris – Procyon the star that’s “Before the dog”

December 15, 2015 Comments off

Ephemeris for Tuesday, December 15th.  The Sun will rise at 8:13.  It’ll be up for 8 hours and 49 minutes, setting at 5:02.   The Moon, 3 days before first quarter, will set at 9:48 this evening.

Visible low in the east at 9:30 p.m. appears the star Procyon to its lower left is Sirius the brightest night-time star.  Procyon is the bright star in the constellation Canis Minor, or lesser dog.  I can find only one other star in Canis Minor.  Perhaps it’s a hot dog.  If Sirius, in Canis major is the Dog Star then Procyon should be the Little Dog Star.  However Procyon is an interesting name.  It means “Before the dog”, which is an allusion to the fact that Procyon, though east of Sirius actually rises before it.  This is due to Procyon’s more northerly position.  This effect doesn’t work south of the equator, however.  Sirius will rise at about 9 tonight.  Procyon is a star much like Sirius but is 32% farther away.  It’s 11.4 to Sirius’ 8.6 light years away.

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

Addendum

Procyon, Sirius and the stars of winter. Created using Stellarium

Procyon, Sirius and the stars of winter. Created using Stellarium

In the above chart, beside the constellation lines, we have the grid of right ascension, from lower left to upper right; and declination, from upper left to lower right.  right ascension lines are like longitude on the Earth, while declination lines are latitude lines.  They are tipped because I don’t live at either the equator or one of the poles.  As the Earth rotates the Sun, stars and planets slide westward in the direction of the declination lines.  Note that Sirius is closer to the horizon than Procyon.  Also that Sirius is west of the 7 hour right ascension line. (Take my word for it.)  Procyon is  east of that line, thus Sirius is west of Procyon.

Other cool things can be seen in the chart.  Note the declination line that touches the horizon at the east compass point and runs just above Orion’s belt.  It is 0º declination, or the celestial equator.  It extends to the west compass point on the western horizon.  The Sun on the equinoxes will rise due east and set due west.  The 6 hour right ascension line runs past Betelgeuse in Orion.  At 23½º north declination, near Castor’s big toe in Gemini is where the Sun appears on the first day of summer, the summer solstice.

P.S. It was cloudy and rainy the last two days.  Didn’t see a Geminid meteor again this year, keeping my record intact.

02/13/2015 – Ephemeris – The stars Castor and Pollux

February 13, 2015 Comments off

Ephemeris for Friday, February 13th.  The sun will rise at 7:46.  It’ll be up for 10 hours and 21 minutes, setting at 6:08.   The moon, 2 days past last quarter, will rise at 3:51 tomorrow morning.

At 9 p.m. the constellation of Gemini the twins will be seen high in the southeast.  The namesake stars of the two lads are the two bright stars at the top of the constellation.  Pollux the pugilist, or boxer, is the lower of the two, while Castor, the horseman, is the other star, or rather a six star system.  In telescopes two close stars may be seen each is a spectroscopic binary, meaning the lines of two stars can be seen in the spectrum.  A faint nearby spectroscopic binary also belongs.    Pollux, though a single star, does have at least one planet, one over twice the mass of Jupiter orbiting the star at a distance somewhat greater than Mars is from the sun.  Pollux is 34 light years away while Castor is 50 light years away.  Not too far away as stars go.

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

Addendum

Gemini with the stars Castor and Pollux

Gemini with the stars Castor and Pollux. Created using Stellarium.

 

Categories: Ephemeris Program, stars Tags: , ,

11/20/2014 – Ephemeris – Constellation rotation from rise to set

November 20, 2014 Comments off

Ephemeris for Thursday, November 20th.  The sun will rise at 7:45.  It’ll be up for 9 hours and 24 minutes, setting at 5:10.   The moon, 2 days before new, will rise at 6:38 tomorrow morning.

At 9 p.m., if it’s clear tonight look to the east to see the bright winter constellation Orion the hunter mostly risen over the eastern horizon as Robert Frost told in his poem Star-Splitter.  Orion’s throwing a leg up over the horizon, climbing into the sky.  The three stars of Orion’s belt are nearly vertical as the mighty hunter rises.  When in the spring he sets those stars will be horizontal.  The same is true on the two namesake stars of the twins of Gemini Castor and Pollux to Orion’s left rising in then east-northeast.  They rise vertically aligned and set horizontally.  It’s due to our latitude and the fact that these stars are near the equator of the sky.  At the poles the stars don’t change attitude, and don’t rise or set.  Here they flip about 90 degrees, and at the equator they do a 180.  Interesting.

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

Addendum

Orion Rising

Orion rising at 9 p.m. on November 20, 2014. Note that Orion’s Belt stars and Gemini’s namesake stars are nearly vertically aligned. Created using Stellarium.

Orion Setting

Orion setting near the end of twilight in April 2015. Note that Orion’s Belt stars and Gemini’s namesake stars are now nearly horizontally aligned. Created using Stellarium.