Posts Tagged ‘Alpha Centauri’

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.


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.

08/16/2016 – Ephemeris – Does Proxima Centauri have a planet? Also some information for southern observers about Mercury

August 16, 2016 Comments off

Ephemeris for Tuesday, August 16th.  The Sun rises at 6:46.  It’ll be up for 13 hours and 59 minutes, setting at 8:46.  The Moon, 2 days before full, will set at 5:53 tomorrow morning.

Proxima Centauri is the closest star to our solar system.  It is a red dwarf star, and a distant third member of the Alpha Centauri star system.  Recently the German weekly Der Spiegel announced that astronomers at the La Silla Observatory in Chile have detected a possible Earth-like planet at a distance that water may be liquid on its surface around this tiny star.  Other than this one leak, no one is talking, and the European Southern Observatory is mum on the subject.  There may be some kind of announcement at the end of the month.  If true, this means that the closest earth-like planet orbits the closest star, only four and a quarter light years away.   That’s nearly 25 trillion miles, and hundreds of years travel time with our current technology.

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


Proxima Centauri chart

Chart showing the location of Proxima Centauri, labeled here HIP 70890. Alpha Centauri is labeled Rigel Kentaurus. Alpha Centauri is actually a catalog name in the style of Johann Bayer’s 1603 star atlas. Note also the alpha (α) Greek letter next to the star. Created using Cartes du Ciel (Sky Charts).

Note also the star labeled Agena.  That is the more distant Beta (β) Centauri also known as Hadar.

Proxima Centauri image

A section of a photograph of part of the field of view of the chart above. Credit: Wikipedia user Skatebiker.


For our southern observers:  Today Mercury reaches its greatest eastern elongation  of 27 degrees.  So it’s visible in the west with Venus and Jupiter.

10/26/2012 – Ephemeris – The planet next door

October 26, 2012 Comments off

Ephemeris for Friday, October 26th.  The sun will rise at 8:12.  It’ll be up for 10 hours and 26 minutes, setting at 6:39.   The moon, 3 days before full, will set at 6:05 tomorrow morning.Last week some astronomers announced the discovery of a planet in the star system next door.  Rigel Kentaurus, better known for some reason as Alpha Centauri, only 4.3 light years away, 25 trillion miles, if your odometer goes that high, is the closest star system to the solar system.  I say star system, because it contains 3 stars.  Star A is much like the sun, star B, somewhat larger and dimmer is orange in color.  These two orbit each other at distances the range from Saturn’s distance from the sun to Pluto’s in about 80 years.  The third star is a distant red dwarf, slightly closer to us than the other two and named Proxima Centauri.  The new planet discovered is in essence hugging star B.  Its designation is Alpha Centauri Capital B lower case b (Bb).

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


Alpha Centauri A and B.  Created using Celestia.

Alpha Centauri A and B. Created using Celestia.

Celestia doesn’t do Alpha Centauri justice.  The A star, to the lower left, is about 1.5 times brighter than the sun.  The B star is half the sun’s brightness.  I wonder how far a planet could be from either star without being in an orbit that would be unstable and be ejected from the system.