M31 Andromeda Galaxy #23 (Molly Wakeling)

M31 Andromeda Galaxy #23

My best Andromeda yet!!

Despite being such a large and bright object (well, actually, because of it), M31 is difficult to capture well. This is attempt #23 since I started doing astrophotography. Being under much darker skies helps -- I took this in West Virginia, at Calhoun County Park, on a trip back in August.

Andromeda, also known as Messier 31, is always a crowd favorite, but I especially love it for the role it played in humanity discovering that the universe was much, much bigger than our galaxy. From its first written mention in 964 AD by Persian astronomer Abd al-Rahman al-Sufi until the early 20th century, it was thought to be a nebula or star cloud within our own Milky Way galaxy. In 1755, philosopher Immanuel Kant proposed that our galaxy was only one of many galaxies. In 1917, American astronomer Herbert Curtis noticed that several novae observed in M31 were many stellar magnitudes dimmer than novae in other parts of the sky. Curtis and astronomer Harlow Shapely had a "Great Debate" about the nature of M31 in 1920, and in 1925, Edwin Hubble observed a particular type of variable star, called a Cepheid variable, in the 100-inch Hooker telescope. Now, Cepheid variables have an intrinsic luminosity associated with their period of variability -- so a Cepheid variable star with a specific period that appeared much, much dimmer can be concluded to be much farther away. This lead to Hubble's estimate of M31's distance to be far greater than previously thought, placing it outside the bounds of the Milky Way. And humanity's perception of the universe changed forever.

I would like to point out the fact that we weren't certain that the universe was any larger than our own Milky Way galaxy until less than a hundred years ago!!

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Status	Advanced success
Started	...
Astrometry.net job	6813382
PixInsight job	RADMME51CKIB7UZJ9N1XUMUY2QTQ1E94
PixInsight queue size	n/a
PixInsight stage	TASK_LOG

RA (center)	00h43m21s.47
RA (top/left)	00h51m10s.69
RA (top/right)	01h07m55s.89
RA (bottom/right)	00h34m26s.10
RA (bottom/left)	00h19m08s.70

Dec (center)	+41°25′17″.8
Dec (top/left)	+37°04′38″.9
Dec (top/right)	+41°42′25″.0
Dec (bottom/right)	+45°44′31″.9
Dec (bottom/left)	+40°49′02″.2

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