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02/17/2017 – Ephemeris – The stars of the Belt of Orion

February 17, 2017 Comments off

Ephemeris for Friday, February 17th.  The Sun will rise at 7:39.  It’ll be up for 10 hours and 35 minutes, setting at 6:14.  The Moon, 1 day before last quarter, will rise at 1:15 tomorrow morning.

Let’s take a closer look at the central constellation of the winter sky, the giant hunter Orion.  His most remarkable feature in his Belt of three stars in a straight line.  It’s the brightest, straightest and most equidistant line of stars I know of.  It points down and left to the brightest star Sirius the dog star and up to the right of Aldebaran the angry bloodshot eye in Taurus the bull.  The star names as taught to me by Grand Rapids Public Museum curator Evelyn Grebel in my youth in the 1950s was from left to right Alnitak, Alnilam and Mintaka.  All the names reference a belt or girdle.   Alnitak lights up a faint cloud that can sometimes be glimpsed with binoculars called the Flame Nebula,  Just below it and invisible except in photographs is the Horsehead Nebula.

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

Addendum

Orion's named stars

Orion’s named stars including the belt stars. Created using Stellarium.

Orion's Belt

Orion’s belt stars showing the nebulae illuminated by Alnitak. The Flame Nebula above left of it and the Horsehead Nebula below.  At this scale the horse’s head figure appears as a dark  bump into the left edge of the red glow.

The Horsehead Nebula

The Horsehead Nebula: On the left in visible light from the National Optical Astronomy Observatory, while the image on the right is from the Hubble Space Telescope’s near infrared camera. Infrared light penetrated dust and gas better than visible light. This image is rotated about 90 degrees counterclockwise from the above image.

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01/26/2017 – Ephemeris – Is it a dachshund or a hot dog?

January 26, 2017 Comments off

Ephemeris for Thursday, January 26th.  The Sun will rise at 8:07.  It’ll be up for 9 hours and 36 minutes, setting at 5:43.  The Moon, 1 day before new, will rise at 7:40 tomorrow morning.

The constellation Orion has two hunting dogs.  We’ve seen Canis Major the greater dog at Orion’s feet with Sirius in its heart.  The lesser dog, Canis Minor is level with Betelgeuse in Orion’s shoulder and off to the left.  Just two stars mark it.  Is it a dachshund or is it a hot dog?  You decide.  It’s brighter star’s name is Procyon which means “Before the dog”, an odd title.  It means that though east of Sirius, it rises before Sirius, due to its more northerly position in the sky.  In many ways Procyon is nearly a twin of Sirius.  It shines with the same white color, although a bit cooler, and has a white dwarf companion like Sirius.  It’s a bit farther away than Sirius’ 8 light years.  Procyon is 11 and a half light years away.  Procyon, Betelgeuse and Sirius make the winter triangle.

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

Addendum

Orion and hunting dogs

Procyon and Orion’s hunting dogs animation also showing the Winter Triangle asterism*. Created using Stellarium and GIMP.

* Asterism – an informal constellation like the Big Dipper, the Northern Cross, or the Summer Triangle.  Not one of the 88 official constellations.

12/27/2016 – Ephemeris – The stars of Orion

December 27, 2016 2 comments

Ephemeris for Tuesday, December 27th.  The Sun will rise at 8:19.  It’ll be up for 8 hours and 49 minutes, setting at 5:09.  The Moon, 2 days before new, will rise at 7:26 tomorrow morning.

The large and bright constellation of Orion the hunter is in the southeast at 9 p.m., with the bright star Sirius below it near the horizon.  The equally spaced line of three stars of Orion’s belt are nearly vertical and point down to Sirius, also known as the Dog Star in Canis Major, Orion’s greater dog.  The whole of its constellation stars aren’t up at 9 p.m., but they will all clear the horizon by 10 p.m.   Those three belt stars are in the center of an elongated rectangle of stars  At the top left of Orion’s shoulder stars is the red giant star Betelgeuse.  The right shoulder star is Bellatrix.  Both Bellatrix and Sirius along with the names of other stars and constellations should be familiar to fans of the Harry Potter novels and movies, as members of the house of Black.  The knee stars at the bottom of the rectangle are, from left to right Saiph and the brilliant blue giant star Rigel.  Between his belt and knees are stars of his sword.

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

Addendum

Orion

Orion, star names, and constellation art animation position for 9 p.m. December 27. Created using Stellarium and GIMP. Artist: Johan Meuris.

In the image above I’ve added the belt star names, though they are generally covered in a program of their own.

11/28/2016 – Ephemeris – The Hyades the star cluster in the face of Taurus the bull

November 28, 2016 Comments off

Ephemeris for Monday, November 28th.  The Sun will rise at 7:57.  It’ll be up for 9 hours and 7 minutes, setting at 5:04.  The Moon, 1 day before new, will rise at 7:45 tomorrow morning.

Rising in the east now is the bright star Aldebaran an orange star that’s at one end of the sideways letter V of stars that is the head of Taurus the bull.  Above it is the jewel-like Pleiades or Seven Sisters star cluster.  There’s more to Taurus, like it’s freakishly long horns and front part of its body.  But you can say you’ve seem Taurus, if you can spot his face.  That V of stars is actually a star cluster called the Hyades, and in Greek Myth were the half-sisters of the Pleiades, also fathered by the god Atlas.  Both the Hyades and Pleiades are being pursued by Orion, which as Robert Frost put it is throwing a leg over the eastern horizon at 8 to 9 pm.  He isn’t the only one following the Pleiades, the name Aldebaran means “The Follower”.

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

Addendum

the Hyades, Taurus, Orion and the Pleiades

An animation showing the Hyades, Taurus, Orion and the Pleiades. Created using Stellarium and GIMP.  Click on image to enlarge.

Closeup of the Hyades and the Pleiades

Closeup of the Hyades and the Pleiades. Created using Stellarium.

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

 

 

 

01/04/2016 – Ephemeris – Some named stars in Orion and how to remember them

January 4, 2016 Comments off

Ephemeris for Monday, January 4th. The Sun will rise at 8:20. It’ll be up for 8 hours and 55 minutes, setting at 5:15. The Moon, 2 days past last quarter, will rise at 3:49 tomorrow morning

Now that the Moon has fled let’s turn to the dark skies of winter and the magnificent constellation of Orion the hunter. At 9 p.m. he’s not yet completely upright in the southeast at 9 p.m. His seven bright stars make him easy to spot, starting with his belt of three stars in a straight line angling down to the left. It is inside a rectangle framing his shoulders and knees, leaning now to the left. The bright reddish star at the upper left corner is Betelgeuse, which according to a certain movie one shouldn’t say three-time in a row. The other shoulder star is a name familiar to Harry Potter fans, Bellatrix, though there’s nothing Lestrange about it. The lower right star is the bright blue-white Rigel. All in all a very impressive constellation.

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

Addendum

Orion's bright named stars

Some of Orion’s star names. Orion at 9 p.m. January 4, 2016. Created using Stellarium.