M33, The Pinwheel Galaxy in Triangulum

Rod Pommier
Location of photo
Pommier Observatory, Portland, OR, USA
Date/Time of photo
2013-12-03 through 2013-12-07
Telescope: Celestron Compustar C14 with AstroPhysics 0.75x focal reducer (f/8.3) Camera: SBIG STL 11000M with SBIG AO-L adaptive optics at 7 Hz and Baader Planetarium LRGB filters. Exposures: LRGB=360:100:100:100 minutes=15 hours total exposure
M33 in Triangulum is a member of our local group of galaxies. It covers an area over 3 times that of the full moon. Although M31 is larger and somewhat closer, it is inclined only 12 degrees to our line of sight, so most of its internal structures are hidden from us. In contrast, M33 is inclined 55 degrees to our line of sight, so it reveals a wealth of internal structure. Although we think of M33 as one object, it actually contains 4 nebulae large enough to have their own NGC numbers and 10 star clouds with their own IC numbers. Nebula NGC 604 at the upper right of the image is one of the largest nebulae known, spanning an astounding 1500 light years.
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