Wednesday, October 18, 2006

The November Sky (2006)

Cassiopeia, in the north, can be recognized by its distinctive ‘W’ shape, though in November it looks more like an ’M’. It sits squarely in the Milky Way and thus abounds in nebulae, clusters, and interesting stars and star clouds. Observers interested in open clusters can spend hours in this constellation. Follow the line from alpha to beta towards Cepheus to find M52, a great open cluster. Other open clusters are NGC 7789, near beta, NGC 7790, between beta and 6 Cass, can be found amidst a string of fainter clusters. Not far from the midpoint of the ‘M’ is NGC 103. Scan the region near kappa to find NGC 133 and NGC 146. M 103 is located near delta. Unlike others in the Milky Way, Cassiopeia is also host to some noteworthy galaxies.

Cassiopeia, being the sole denizen of the Milky Way, is unique among November constellations. For the most part, the sky this month lacks objects associated with our galaxy. In exchange, we find our gaze directed towards other galaxies, most them rather faint and hard to find. The Local Group members M31, M33 and the Small Magellanic Cloud however, rival most other deep sky objects.

South of Cassiopeia is Andromeda, two major strings of stars streaming north-east from the Square of Pegasus. The most notable object is M31, the Andromeda Galaxy. This can be found by following the line defined by beta and mu northwest. M31 is a great sight in any telescope. M32 and M110 (NGC205) are part of the M31 system. Observers with larger telescopes can try to pick out the globular clusters of M31. Large telescopes will also allow one to observe an impressive number of fainter galaxies throughout Andromeda. Binoculars reveal a number of pretty star strings in this region. Gamma is a popular multiple star: look for it at the easternmost ‘foot’ of the princess. Even small telescopes will split the major components which present a striking yellow-blue contrast.

Not far from Andromeda is tiny Triangulum. The major object here is M33, found by slowly scanning from alpha towards beta Andromedae. The galaxy appears face-on to our perspective and is often called the “Pinwheel Galaxy”. It is fainter than M31 but a remarkable object nonetheless. As with M31 and other famous deep-sky objects, first-time observers may find themselves spoiled by the memory of the many outstanding photographs of this object. Take the time to observe for signs of spiral structure or for uneven clumps of brightness. Averted vision will help in discerning details that might otherwise elude you. Triangulum hosts a number of other galaxies but none compare with M33.

South of Triangulum is humble Aries. There are many double and multiple stars in this region although most of them are rather faint. Deep-sky enthusiasts will excellent conditions and large telescopes to find much of interest here.

The eastern fish of Pisces borders Aries. This string of stars extends roughly north from alpha running all the way to Andromeda. There are a number of faint multiple stars but the primary object of interest is M74, a tiny version of M33. Look for it east of eta. You will need dark skies to locate it and, due to its compact nucleus, it may resemble a poorly defined globular cluster rather than a spiral galaxy.

South of Pisces is the large, rambling constellation Cetus. Cetus consists of a large circle in the west connected by a string to a smaller circlet to the northeast. The midpoint of the connecting string is occupied by Mira, a variable star that cycles through a six-magnitude change in roughly 330 days. Among the interesting double stars of Cetus are alpha, gamma, 66 (near Mira), and 26 Ceti. M77 is a small but surprisingly bright object, a strange galaxy with a tremendous amount of energy generated in its nucleus.

Due east of Fomalhaut is indistinct Sculptor. This area presents us with faint stars and fainter galaxies. There is one open cluster, Blanco I, that requires wide field binoculars to appreciate fully. The galaxies here are mostly members of the Sculptor Group, a neighbor of our own Local Group of galaxies.

Southern observers are able to observe two exceptional objects this month. The Small Magellanic Cloud and the spectacular globular cluster 47 Tucanae.


The Planets in November

Mercury transits the sun on November 8.

Venus is a difficult object for northern observers. Southerners have a slightly better view.

Mars is not visible this month.

Jupiter can be seen by southern observers in the early morning sky.

Saturn is in the morning sky.

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