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02/08/2018 – Ephemeris – The wonderfully named stars of Orion

February 8, 2018 Comments off

Ephemeris for Thursday, February 8th. The Sun will rise at 7:53. It’ll be up for 10 hours and 8 minutes, setting at 6:01. The Moon, 1 day past last quarter, will rise at 3:09 tomorrow morning.

The constellation of Orion the hunter is visible in the south at 9 p.m. The stars of Orion are interesting in themselves. Starting at the top left of the seven bright stars of Orion’s torso is Betelgeuse the bright red star, whose name means something like “Armpit of the Giant”. The star in Orion’s other shoulder is Bellatrix the “Amazon Star”. Below are the three stars of Orion’s belt, from left to right; Alnitak, Alnilam and Mintaka. Their names mean “Girdle”, “Belt of Pearls”, and “Belt” respectively. Down to Orion’s knees we look on the left to the star Saiph pronounced ‘safe’ which means “Sword”, though it is some ways from the stars of Orion’s sword. Finally there’s the bright blue-white star Rigel whose name means “Left Leg of the Giant”.

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

Addendum

Orion with star names.

The named stars of Orion. Created using Stellarium.

Betelgeuse, pronounced Beetlejuice is the name of a 1988 movie, where Betelgeuse (spelled properly) is a particularly mischievous demon.  Don’t say his name three times, or he’ll come and ‘help’ you.  Oops, I did.  It is a red giant star near the end of its life.

Bellatrix, is now known to most of us now as the first name as the first name of Bellatrix Lestrange from J. K. Rowling’s Harry Potter book and movie series.  Other members of the Black family have astronomical names, such as Regulus (Leo) Black, and Sirius (Canis Major) Black.

The names of the belt stars were taught to me by Evelyn Grebel of the Grand Rapids Public Museum in the late 1950s.  She was one of the founders of the Grand Rapids Amateur Astronomical Association.  The names Alnitak, Alnilam and Mintaka have stuck with me ever since.  It was through her that I was able to worm my way into working at the museum’s new then unnamed planetarium.  I also remember being in her office with her, listening to the radio as Alan Shepard made his historic suborbital flight on May 5th, 1961.

Rigel is a hot blue-white star, and will probably become a red giant star like Betelgeuse.  There is another bright star named Rigel, but most don’t know it.  It’s Rigel Kentaurus, the leg of the centaur of Centaurus.  It’s better known as Alpha Centauri, a catalog designation, and the nearest star to the solar system.

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12/04/2017 – Ephemeris – Orion rising in the moonlight

December 4, 2017 1 comment

Ephemeris for Monday, December 4th. The Sun will rise at 8:02. It’ll be up for exactly 9 hours, setting at 5:02. The Moon, 1 day past full, will rise at 6:32 this evening.

Now that the Moon is quite bright and making the fainter stars in the constellations harder to find, let’s look at one of the bright stars of Winter. Tonight at 8 p.m. the bright reddish star Betelgeuse is low in the east, but will be rising higher and moving slightly southward, as the rest of the bright stars in its constellation of Orion the hunter also clear the horizon. To its right are a nearly vertical line of three equally spaced stars, Orion’s belt. Betelgeuse is in Orion’s shoulder. The name Betelgeuse is a corruption of the Arabic phrase “Armpit of the Central One”, although there’s some debate about that translation. Betelgeuse is maybe only 7 million years old, but due to its great mass of up to 20 times that of the Sun, is already dying.

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

Addendum

Orion rising

Orion rising in the light of a super moo at 8 p.m.,, about 3 hours after sunset, December 4, 2017. Created using Stellarium.

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.

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