Oct 21, 2010

M31

So begins my astronomy series based on photos taken by the camera mounted on the 24" telescope at Pine Mountain Observatory, Summer 2010. Taken by Eric Holcomb. Encouraged by moi. The camera mounted to the telescope does not show what we actually saw through the telescope, but it gives me pictures to use while talking about various astronomical objects in the northern skies.


M31 is better known as the Andromeda Galaxy. Charles Messier catalogued 103 objects. The list took on a life of its own afterward and now totals 110. Messier was actually looking for comets, so catalogued fuzzy objects that might be comets. Fuzzy they often are. The smaller the telescope, the fuzzier they look.

Andromeda is the closest galaxy to our own. Approximately 2.5 million light years away. A light year is about 6 trillion miles. So the distance is 6 trillion x 2.5 million. Yup, that's a lot of zeros. It is a spiral galaxy like our own Milky Way and part of our local group. Galaxies travel in clusters. Our group consistes of M31, M32, M33, M110 and the Large and Small Magellan Clouds, which can be seen without a telescope in the Southern Hemisphere.

Andromeda is large and bright in telescopes. On a dark night, you can see its two companion galaxies - M32 and M110 - in smaller scopes with an eyepiece that gives a wider field of view. It spans a 32mm eyepiece in my 8" dobsonian.

Andromeda is visible to the naked eye on a dark night. I'm always pointing it out up at PMO. It is easier to see with averted vision [not looking directly at it]. You just need to know where to look.


The three galaxies are always a showstopper when I can show them. When the moon is bright, Andromeda is still usually visible in a telescope. Because of it's size and brightness, it is one of the easier objects to find, if you know where to look. It was the first object I found on my own. Istill love to gaze at it and its companions.