New image- our neighbor Andromeda

Our nearest “major” galaxy neighbor, M31 Andromeda at “only” 2.5 million light years distant

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 100″ Hooker telescope at Mt Wilson. From the early 1900’s until the 1930’s, when the Hale 200″ telescope at Mt Palomar saw first light, this was the largest telescope in the world and was the instrument that enabled Hubble to determine that the “Andromeda nebula” was actually a distant galaxy outside our own! While I never had the opportunity to look through it I do remember our tour guide warning us not to lean against the observatory walls as the exposed DC circuitry would likely electrocute you!

In the summer of 2003, I had the good fortune to be able to spend 2 weeks at Mt Wilson where I did a spectroscopy project. In the basement of the observatory housing the Hooker 100″ telescope were the lockers of the scientists but it was very dark when I tried to take this picture of Edwin Hubble’s locker!

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