The Milky Way galaxy is part of a Local Group of Galaxies that together occupy a space some 10 million light years in diameter. As “Ellie” Arroway says in Carl Sagan’s novel Contact, if there isn’t intelligent life out there, it’s an awful waste of space.
Today’s image is M31 – The Andromeda Galaxy. M31 is the largest known member of the Local Group. The Milky Way is the second largest, and M33, the Triangulum galaxy, is the third largest. I’ll post M33 tomorrow.
The Local Group consists of at least 80 member galaxies. Most of them are small, so-called dwarf galaxies. Andromeda has a dozen or more satellite galaxies. The image below shows Andromeda and some of its satellites. M110 is the spiral galaxy just below and to the right of Andromeda. M32 is the spherical galaxy to the left of Andromeda’s central bulge.
This image is the composite of 17, 6-minute exposures taken from Casitas de Gila dark site. This image is not cropped; it shows the complete field of my full frame DSLR camera.
In the past, I have posted other images of Andromeda using this same astrograph as well a larger 130mm astrograph. While I think that this is my best effort thus far, I have not taken this little astrograph to its limits. The truth is that there are dedicated astrophotographers who, using similar equipment, record a dozen hours or more data in order to produce absolutely stunning images of Andromeda and other objects. If I lived in a truly dark sky site, I might try that. Alas, I can only vacation in such spots, and I feel fortunate that I can do so.
