Tag Archives: Andromeda Galaxy

Andromeda Galaxy (M31)

M31boboThe Andromeda Galaxy is the Milky Way’s closest galactic neighbor. At 2.5 million light years away, it is rather large, spanning about 3° of the sky (about the width of six full Moons), and can be seen with the unaided eye when viewed under clear dark skies. As opposed to dramatic spiral arms that appear in photographs, M31 appears as a fuzzy blob of light, which is actually the Andromeda Galaxy’s core, when viewed with binoculars or a modest telescope. Consult a start chart to locate this object in the Andromeda constellation. If you do happen to view this object under a clear, dark sky, and without optical aid, then the answer to “how far can I see?” becomes 2.5 million light years!


Andromeda (Cassiopeia’s daughter)

Andromeda, CassiopeiaAndromeda, the mythological daughter of Cepheus and Cassiopeia, is located near these two constellations and among several other constellations representing the Perseus myth, to include Perseus, Pegasus, and Cetus. It is one of the 48 constellations cataloged by 2nd century astronomer Ptolemy that remain among the 88 modern constellations. It is found directly overhead at the zenith after sunset in December. Although Andromeda is not a very distinct constellation in light-polluted skies, most of its stars can be observed. It’s brightest star, Alpheratz (Alpha Andromeda), is shared with the constellation Pegasus, and marks one corner of the Great Square of Pegasus. Locate this constellation by starting with the north eastern most star of the Great Square of Pegasus, and find the remaining stars flowing north east from there.

The Andromeda Galaxy (M31), M31boboThe Milky Way’s closest galactic neighbor, is found in this constellation. M31 can be found with the unaided eye in the very darkest of dark skies, but can easily be found with a binocular or telescope under most adverse light pollution conditions. M31 and M110 are two of M31’s dwarf companion galaxies that can also be seen in most photographs of M31.

IAU Andromeda chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 4, 2011.
IAU Andromeda chart, IAU and Sky & Telescope magazine (Roger Sinnott and Rick Fienberg), June 4, 2011.

© James R. Johnson, 2014