Our nearest major galaxy neighbor at 2.5 million light years with similar size but almost twice as many stars. (Of course we are not counting the irregular dwarf galaxies Magellanic Clouds which are only 200,000 light years from us, but only about 10% of the Milky Way’s diameter ). Amazingly it was not known that this was a galaxy outside our own until astronomer Edwin Hubble made the discovery in 1923. Just think about that for a second: less than 100 years ago we still thought the Milky Way was all there was in the Universe! I had the opportunity to visit Mt Wilson in 2003 and tour the 100″ Hooker telescope where Hubble made his famous discovery . Observations of variable stars within Andromeda enabled the distance to be calculated and at that point in history the universe suddenly become a lot bigger!
The Andromeda galaxy is located in the constellation of the same name and in a reasonably dark sky it can be spotted with the naked eye in late Summer and Fall.
Capture info for above image (see the thumbnail image link on the lower right hand side of this page for the full resolution version- under “My Astroimages):
Location: Orion’s Belt Remote Observatory, Mayhill, New Mexico
Telescope: Takahashi FSQ 106N
Camera: SBIG STXL 6303E
Mount: Paramount MX+
Data: LRGB 5,4,5,6 hours respectively
Processing: Pixinsight
Thanks for reading!
DrDave