Messier 33, also known as the Triangulum Galaxy is the third largest galaxy in our local group of galaxies (behind the Andromeda galaxy and our own Milky Way). It is about 2.73 million light years away. It is one of the most distant objects visible to the naked eye though it takes an exceptionally dark sky for it to be visible.
M33’s apparent width is just over one degree making it twice as wide as the full moon and it’s height is about ⅔ of a degree making it a bit larger than the full moon. Basically if you put two full moons side by side you have a good idea of the area M33 covers in the sky.
This image is 14.7 hours worth of RBG data and was acquired over the fall and early winter. It was my secondary target. Whenever the first target of the night went behind the neighbor’s tree I’d switch fo M33 and finish off the night on it.
Processing was relatively straightforward. It started with drizzle integration with the intent of doing deconvolution however deconvolution caused problems with the edges of the bright stars on masked stretch so I decided to omit deconvolution.
I have a hydrogen alpha filter on order and was hoping it would arrive in time to add some data to this image but it’s ETA is not known yet so I decided to publish this for now. If it does arrive before M33 sets for the season I plan to try an Ha-RBG version of this.
For all the technical details about this image, you can see it on astrobin.