Another image captured from SRO in California, M 31 is a favourite of northern hemisphere imagers. What they don't tell you is how bl**dy difficult it is to process! I've tossed away a lot of earlier attempts
Captured at SRO, 17 Sep - 30 Oct, 2015
Objects in image:
M31, M110, M32, NGC206
Scope: Ceravolo C300 @ f/4.9 = 1470mm FL
Mount: AP1100
Camera: FLI PL16803
Focuser: Atlas
Filters: Astrodon
Guiding: Lodestar II / Tak guide scope
Image scale: 1.26 arcsec/pixel (drizzled to higher res)
Exposures: 20x1200s + 6x60s R, 17x1200s + 6x60s G, 19x1200s + 6x60s B, 27x1800s Ha (~32.5 hours)
Processing: PixInsight 1.8
Acquisition credit: John Kasianowicz, Daniele Malleo, Leonardo Orazi, Rob Pfile, Rick Stevenson and Jerry Yesavage.
Processing credit: Rick Stevenson
High res version on Astrobin (check out the 1:1):
http://www.astrobin.com/full/223013/0/
The attached images show the location of M31-V1, the Cepheid Variable used by Hubble to calculate the approximate distance of the Great Andromeda Nebula and finally prove that it was a separate galaxy distant from the Milky Way (thanks to RobF for the idea!)
There's a fascinating atlas of the Andromeda Galaxy here:
https://ned.ipac.caltech.edu/level5/...as/frames.html
Cheers,
Rick.