a galaxy far, far away
While in the Arizona desert for Thanksgiving, I was treated to the wonderful dark sky we city folk seldom get to enjoy.
Considering there are billions if not trillions of galaxies in the observable Universe, It's mind boggling that almost everything we can see from the Northern hemisphere with the naked eye is part of our own Milky Way Galaxy. There's one significant exception: the Andromeda Galaxy, aka Messier object 31. It's very dim and hard to spot without knowing where to look in a dark sky. I've never seen it, at least that I noticed, but I inadvertently photographed it Thursday night.
While everyone else was watching the Ravens beat the Steelers, I took a few generic shots of the starry sky by laying the camera on the ground and pointing straight up. Packing light, I'd brought the 6D with only the 40mm f2.8 lens. Exposure was 8 seconds at f4, focus set at infinity and sensitivity at ISO 25,600. Looking at the shots in PhotoShop the next day, I recognized a galaxy shaped blur. I looked up where Andromeda was supposed to be and overlaid star charts to see if my hunch was correct. It was.
The first written reference to the Andromeda Galaxy was by Persian astronomer Abd al-Rahman al-Sufi, who described it in 964 CE as a "small cloud." Centuries would pass before anyone figured out that this blur of light in the constellation Andromeda was outside of our own Milky Way. When Isaac Roberts, fof Sussex, England, took the first photographs of M31 in 1887, the object was still commonly believed to be a nebula (interstellar cloud) within our galaxy. In the early-1920s Edwin Hubble (yes, that Hubble) demonstrated through spectrographic observations that Andromeda and many other objects were galaxies in their own right, in a vast sea of galaxies.
Andromeda is a large spiral galaxy estimated to contain about 1 trillion stars (1,000,000,000,000), or roughly a four times the stellar population of our own galaxy. It is roughly 2.5 million light years from Earth, meaning the light photons reaching the Canon 6Ds sensor this week had departed from the surface of stars in Andromeda about 2.5 million years ago. Cool, eh?
The 6D looks like it would be a great tool for astrophotography. I want to take another crack at this, with a longer lens and a lower ISO (and tinkering with noise reduction), I think you might be able to make out structure in the arms of the galaxy.
Most facts cited above are derived from Wikipedia entries. Especially see en.wikipedia.org/wiki/Andromeda_Galaxy