Messier 33 is the third largest of the galaxies in our local group behind Messier 31 (Andromeda) and our own Milky Way. It’s a little over three million light years away and combined with being smaller than M31 (in an absolute sense) helps it fit into a field of view that just won’t hold all of M31.

Because of it’s more face-on orientation to us compared to M31 we can also see more detail in the galaxy and because it’s dynamic range isn’t as large, it’s easier to show detail throughout the galaxy.

This is the third time I’ve imaged M33 and it’s probably not the last. So far, each time has been with a different telescope/camera combination and each time I’ve had new techniques to apply to it. This version is probably the most successful in showing detail in the galaxy and also in blending hydrogen alpha emissions into the broadband image. The sheer number of emission nebula in the galaxy is astounding!

This is 40h 55m of HaLRGB data. For all the technical details, see astrobin.