What’s Up This Week – December 26 – December 31, 2005

NGC 2262 (Hubble Variable Nebula). Image credit: Hubble. Click to enlarge.
Monday, December 26 – It’s been awhile since we’ve stayed up late, so why not tonight? Tonight let’s use the later rise of the Moon to our advantage and head about 2 degrees northeast of star 13 in Monoceros. Our study will be NGC 2261 – more commonly known as “Hubble’s Variable Nebula.”

Named for Edwin Hubble, this 10th magnitude object is not only very blue in appearance to larger apertures, but is a true enigma. The fueling star, variable R Monoceros, does not display a normal stellar spectrum and may be a protoplanetary system. R is usually lost in the high surface brightness of the “comet-like” structure of the nebula, yet the nebula itself varies with no predictable timetable – perhaps due to dark masses shadowing the star. We do not even know how far away it is, because there is no detectable parallax!

Tuesday, December 27 – Born today in 1571 was Johannes Kepler – Danish astronomer and assistant to Tycho Brahe. Kepler used Brahe’s copious notes of Mars’ positions and formulated the three laws of planetary motion. These laws are still in use today.
So, if you haven’t been studying law… Have you been studying Venus? Right now its super-slim crescent is visible even to binoculars. Rapidly heading towards the Sun, in the next two weeks watch as it disappears, and then reappears in the morning sky by mid-January. Now that’s Kepler’s laws in action!

For a real challenge, try spotting IC 2118 about a thumb’s width west of Beta Orionis before it sets. “The Witch Head Nebula” is a huge area of reflection illuminated by Rigel, but is very faint. With excellent conditions you may be able to spot some patches of nebulosity.

Wednesday, December 28 – If weather provides you with clear skies this evening, let’s work on a study that is within both binocular and telescopic ability. Wait on Orion to rise well, then turn left at Betelgeuse and you will find open cluster NGC 2244 about 2 degrees east of Epsilon Monoceros.

Containing around two dozen resolvable stars, a good, dark night will treat binocular and low power telescope users to NGC 2237 – the “Rosette” nebula. Surrounding this pretty open cluster like a faint, misty wreath, the Rosette may be one of the most massive nebulae known. It is possible that the star cluster may have used all the “raw material” in its formation, leaving the center clear…and it is equally probable that the intense radiation of these hot, young blue stars simply blew away the gas. Either way, this pair will become an annual favorite.

Thursday, December 29 – Heads up to my friends “down under!” On this universal date, the Moon will make a spectacular occultation of Antares for northern Australia. Be sure to check IOTA information well before this event so you’re ready! Wishing you the best of skies…

Today we celebrate the birth of Arthur S. Eddington. Born in 1882, Eddington was a British theoretical astrophysicist who was key in interpreting and explaining the nature of stars. He also coined the astronomical phrase “expanding universe” to refer to the mutual recession of the galaxies.

Tonight let’s have another look at M77, located less than a fingerwidth south of Delta Ceti. This bright, compact, 10th magnitude spiral galaxy can reveal its arm structure to even small telescopes under good conditions. So what’s so special about it? It was one of the first two systems in which a substantial redshift was detected. It’s moving away from us at a speed of 620 miles per second!

Friday, December 30 – It’s New Moon and tonight let’s grab the binoculars and hunt the “Hunter” – Orion. In the northern-most corner of the constellation and just under Taurus, look for a large, kite-shaped collection of stars known as Collinder 65. You’ll find its mixed magnitude stars span almost half the field of view of average binoculars!
Now let’s go for the “head.” The triangular pattern of stars that marks the hunter’s head is home to Collinder 69. The northernmost – Lambda – is the brightest in a cluster of a double handful of stellar gems. Look for a chain of three!

Are you ready for a “belt?” Then check out the three stars that form Orion’s waistline, because as a group these are known as Collinder 70. Not only is the trio a member of the collection, but there are around 100 stars that belong to this expansive open cluster!

Saturday, December 31 – Today is the birthday of Robert G. Aitken. Born in 1864, Aitken was a prolific American observer who discovered and catalogued more than 3100 double and binary stars.

So often double stars are offered up for the telescope, but it seems that very few are suited to binoculars. Tonight will change all that as you have a closer look at the western-most star in Orion’s belt – Mintaka. This beautiful, white, third magnitude star has a white, sixth magnitude companion to its northeast. Separated by almost a half light-year, these twin stars will be a delight, but telescope users might want to have another look. There’s a third, very faint star to the southwest of the primary!

And so, my friends, this brings us to the close of another observing year. What does 2006 have in store? Be sure to stay tuned… Because there is a surprise coming your way! For now, may the New Year bring peace, joy, and prosperity to all of you wonderful readers around the world! May all of us travel at… Light Speed! ? ~Tammy Plotner