The Triangulum Galaxy is a spiral galaxy approximately 3 million light years from Earth in the constellation Triangulum. It is catalogued as Messier 33 or NGC598, and is sometimes informally referred to as the Pinwheel Galaxy, a nickname it shares with Messier 101. With a diameter of about 50,000 light years ,the Triangulum Galaxy is the third-largest member of the Local Group of galaxies, which includes the Milky Way Galaxy, the Andromeda Galaxy and about 30 other smaller galaxies.

It is one of the most distant permanent objects that can be viewed with the naked eye (depending on viewing conditions).

The Triangulum Galaxy was probably discovered by Italian astronomer Giovanni Battista Hodierna before 1654. It was independently discovered by Charles Messier on the night of August 25–26, 1764, and published in his catalog (1771) as object number 33; hence the name M33.

It was among the first "spiral nebulae" identified as such by Lord Rosse (1850). John Charles Duncan and Max Wolf discovered its variable stars (1922-23). Edwin Hubble showed in 1926 that 35 of these stars were classic cepheids, thereby allowing him to estimate their distances. The results were consistent with the concept of spiral nebulae being independent galactic systems of gas and dust, rather than just nebulae in the Milky Way. Triangulum may be home to 40 billion stars, compared to 400 billion for the Milky Way, and 1 trillion (1000 billion) stars for Andromeda. (Source Wikipedia)

The image was captured with a Meade 12"LX200, using the Canon XSi mod (at F5.8), and Atik 383L+ mono (at F6.3).

DSLR: A total of 35 subs at ISO1600 and 5 minutes each (2.92 hr) on 12/01.

CCD: A total of 66 subs with binning 1x1 and -10C at 10 minutes each (11.00 hr) on 11/20 (15), 11/23 (26), and 11/29 (25) .

Processing was done with PixInsight. This is a medium crop, due to differences in FOV between the two cameras. Cameras were rotated, and North is towards upper left hand corner. At the 6.3 focal length, the field of view is just a bit too small and the image is cramped.

This was the combined mono CCD image and the color DSLR image. First time in a long time I did not use the Orion Skyglow filter. Can't see any difference. As is my failing, it's a bit over-processed.