Contents

The Night Sky in November 2011

By Harry J. Augensen

Professor of Physics & Astronomy, Widener University

Moon’s Phases
Full "Frost" Moon on the 10thNew Moon on the 25th 

Stars and Constellations

Once our clocks go back to Standard Time in early November, the sky becomes dark shortly after 5 pm and stargazing can commence. The star groups of summer are now just a memory, with one notable exception: the "summer" right triangle of Vega, Deneb, and Altair, which can still be seen high in the west. On the other hand, the stars of autumn reach their full spendor on November evenings. High in the northeast is the familiar "W" shape of the constellation Cassiopeia, followed by Perseus, which represents the hero of mythology who rode the winged horse Pegasus and rescued Andromeda from Cetus, the Sea Monster (the Whale in modern times). The constellations of Andromeda and Cetus are both relatively faint, but the Great Square of Pegasus, which sits high in the south by around 8 pm, is quite distinct. The Great Square is comprised of four stars, known as Alpheratz, Markab, Scheat, and Algenib, all of which are much more luminous than our Sun. But, because they are located at distances ranging from about 70 light years for Alpheratz to 500 light years for Algenib, they appear as mere points of light. Below the Great Square is the solitary bright whitish star Fomalhaut in Pisces Austrinus (the Southern Fish). The name Fomalhaut is translated as "mouth of the fish."

Cetus is the fourth largest constellation in the sky, but most of its stars are relatively faint (because they are so distant). Nevertheless, Cetus contains at least one star which is celebrated because it appears to vary greatly in brightness: Omicron Ceti, also known as Mira (meaning the Wonderful One). Mira is featured in University of Illinois astronomer James Kaler’s book, The Hundred Greatest Stars (New York: Copernicus Books, 2002). Mira was discovered by the German astronomer David Fabricius in 1596 (over a decade before the telescope was invented), and has become famous as the prototype for an entire class of stars which vary in light over long periods of time. Mira is an enormous red giant star, of around 350 times larger than our Sun; the latest distance estimates put Mira at around 420 light years from our solar system. Spectroscopic analyses show that it expands and contracts over a period of about 11 months, and it is this phenomenon that causes Mira to change in brightness. Modern astronomers know that Mira is going through a late and unstable phase in the evolution of a normal star (like our Sun) which results in extreme mass loss and in the eventual metamorphosis into a tiny white dwarf star. In fact, the Sun is expected to undergo this phase in roughly five billion years. Interestingly, Mira has a faint companion star known as Mira B which is itself a white dwarf.

Although winter officially begins in December, a few winter stars can be previewed on November nights. One of the brightest of the early winter stars to make its appearance on November evenings is yellow-white Capella (meaning "little she goat"), situated in the constellation of Auriga (the Charioteer). It is low in the northeast around 8 pm, but if you stay up late, Capella will pass nearly overhead around 1 am at midmonth. In the east you may spot the stars of Taurus, the Bull, which contains the bright reddish star Aldebaran. Aldebaran appears to be part of a "V" shaped cluster of stars known as the Hyades. Even more famous is the Pleiades cluster in Taurus, a beautiful, compact group of stars shaped like a miniature dipper.

  Naked-Eye Planets In the Evening and Morning Sky

In the early evening sky, Venus continues to slowly but steadily increase its separation from the Sun following conjunction back in August. At the beginning of November, Venus sets only about an hour after sunset, and may be difficult to locate low above the western horizon, especially if there are obstructions. By month's end, Venus is setting a little less than two hours after the Sun, and can best be spotted about half an hour to an hour after sunset; it resembles a brilliant yellow star low in the west.

As November opens, Mercury is setting only about 45 minutes after the Sun, and will be a challenge to locate hovering below the much brighter Venus and just barely above the western horizon. Things improve a bit toward mid-November, when Mercury reaches greatest evening elongation with the Sun (specifically on the 13th), when Mercury sets over an hour after sunset. Your best bet is to find Venus and scan just below it, ideally about 30 minutes after sunset. Mercury sinks rapidly toward the Sun during the closing weeks of November, and will vanish into evening twilight by month’s end.

Jupiter reached opposition with the Sun at the end of October, and it continues to shine magnificently nearly all night long throughout November. During the early evening hours, Jupiter resembles a brilliant cream-colored star located in the constellation Aries near the eastern border with Pisces and just above Cetus. At midmonth, Jupiter is already well up in the east as evening twilight ends; it transits the meridian at around 10:30 pm, and sets in the west at 4:30 am EST. Since Jupiter is visible most of the night, this is an excellent time to view it through a telescope, which will reveal distinct cloud bands in its atmosphere and also its four Galilean moons.

Mars rises in the northeast at around midnight EST at midmonth, and resembles a bright orange-red star. Mars now resides in the constellation Leo, and is somewhat brighter than nearby Regulus, Leo's brightest star. While not very impressive now, watch for Mars to increase substantially in brightness during the winter months.

Saturn was in conjunction with the Sun last month, but it is already up in the morning sky before dawn. As November begins, Saturn rises nearly one and a half hours before the Sun; by the 30th, this interval increases to three and a half hours. Look for Saturn about an hour before sunrise low in the east; it looks like a bright cream colored star located near Spica, a true star of bluish white color and of roughly the same brightness in the constellation Virgo.

The Leonid Meteor Shower is expected to reach its peak after midnight on November 17th. Look generally toward the east where the constellation Leo will be rising, although meteors can be seen in any part of the sky. Unfortunately, the last quarter moon will wash out many of the fainter meteors until the early morning hours, so try to view before the moon rises.

Information on lunar phases and rise/set times of Sun and planets is obtained from the US Naval Observatory Data Services at http://www.usno.navy.mil/astronomy/. Additional information comes from Astronomical Calendar 2011 by Guy Ottewell (Raynham, MA: Universal Workshop, 2011)Times given apply for observers near to the latitude and longitude of Philadelphia, USA: 40 degrees North latitude, 75 degrees West longitude.

For more information on astronomy and weather, visit http://www.widener.edu/stargazing/, then click on Web Links & Resources. A set of free sky maps can be obtained at http://www.skymaps.com/