Andromeda

Our Constellation report is an easy way for people to become familiar with the nighttime sky. We'll discuss myths associated with the various constellations as well as describing the numerous deep sky objects residing in the area. No equipment is required to view the constellations, though a star chart can be quite helpful. This ease of observing makes constellations a natural place to begin your journey to the stars. 

This weekend we move on to the constellation Andromeda. 

Andromeda was  the daughter of King Cepheus and Queen Cassiopeia of Ethiopia. When Cassiopeia boasted that Andromeda's beauty exceeded that of the sea nymphs, the nymphs prevailed upon Neptune, the god of the sea, to punish Cassiopeia. Neptune sent the sea monster Cetus (sometimes known more favorably as simply a whale) to ravage the kingdom of Cepheus. When Cepheus consulted an oracle for advice, he was informed that only the sacrifice of Andromeda to Cetus the Sea Monster would appease the gods. Thus chained to a rocky cliff, she was rescued by Perseus, who turned Cetus into stone by flashing the face of Medusa before the monster's eyes. Perseus was carried there just in time by the winged horse Pegasus.  

Andromeda's Wonders

Ok, let's start things off the biggest and baddest galaxy visible in northern skies, M31 The Andromeda Galaxy(mag3.47). There are so many superlatives which are fitting for Andromeda: Andromeda lies some 2.3 million light years distant, making it the nearest major galaxy to our own. It is also the most distant object visible to the naked eye. The two small fuzzy objects also visible in this image are actually galaxies. They are M32 and M110. We'll get to these galaxies shortly. Astronomers estimate the mass of Andromeda at over 300 billion suns. This is almost twice as massive as our own Milky Way galaxy. Additionally, it spans over 130,000 light years or roughly 3° -- nearly 6 times the diameter of the full moon! Andromeda is visible in virtually any telescope or binoculars. In larger telescopes, it displays one or more prominent dust lanes. It is a site to behold in the ObDob. The bright patch on the left side of the image is actually NGC206 -- a bright star cloud in Andromeda itself. We always spend time on Andromeda at Utah Skies Star Parties. 

This shot of Andromeda was taken by Don Brown from Park City.

Next up is a neighbor of Andromeda M32(mag8.2). M32 is what is known as a dwarf elliptical galaxy. M32 requires a substantial amount of magnification to reveal any detail. At low powers it is simply a soft fuzzy circular patch that almost appears to be an appendage to M31.

Still in the same low power field of view, we have Elliptical Galaxy M110(mag8.0). Throw some magnification at this object and you'll be rewarded with some fine details. It has a mottled core which is caused by an irregular clumping of stars. Were this object anywhere else in the sky it would get much more attention. Located, as it is, in the same field of view as the giant Andromeda galaxy causes it to be virtually overlooked.

Curiously, this galaxy was discovered by Charles Messier on August 10, 1773, and depicted on his fine drawing of the "Great Andromeda Nebula" and its companions  published in 1807, but Messier did never himself include this object in his catalog, due to unknown reasons, perhaps a certain sloppiness in recording. It was the last additional object, added finally by Kenneth Glyn Jones in 1966. Independent of Messier's discovery, Caroline Herschel discovered M110 on August 27, 1783, little more than 10 years after Messier, and William Herschel numbered it H V.18 when he cataloged it on October 5, 1784. 

M110 is about the same distance as the Andromeda galaxy M31, roughly 2.9 million light years. It's mass is estimated to be between 3.6 and 15 billion solar masses.

Don Brown captured this image in November of 2004.

Next up is NGC7662(mag8.6), The Blue Snowball Nebula. This interesting little planetary nebula is reported to be visible in a good pair of binoculars. In an 8" telescope, it appears as a circular blue patch. In larger apertures, it begins to turn an aquamarine shade. This is an object that definitely handles increased magnification well. The more power you throw at it, the more detail it reveals.
Who says (observational) astronomy is black and white?

Next, check out Open Star Cluster NGC752(mag5.7). This beautiful open cluster spans almost a full degree in diameter. It appears as a loose grouping of over 60 stars in telescopes in the 6-8" range. Located only 1200 light years away, this very old cluster is almost 2 billion years old.

Our final stop in Andromeda leads us to this weeks Utah Skies Challenge Object, Edge-on Galaxy NGC891(mag10). This is one of the finest examples of an edge-on galaxy. It is a small cigar-shaped galaxy with a beautiful dust lane running through its center.
Located about 3.5* east of Gamma Andromeda, this beauty is clearly visible in an 8" telescope. With increased magnification and averted vision, you can begin to make out the dust lane. In larger instruments under dark skies, the views are amazing. Current estimates place its distance at around 31 million light years.

This amazing shot was taken by The WIYN Observatory. The WIYN Observatory is owned and operated by the WIYN Consortium, which consists of the University of Wisconsin, Indiana University, Yale University, and the National Optical Astronomy Observatories (NOAO).

Good Luck!

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