Messier 33 is a spiral galaxy located in the constellation of Triangulum, for that reason it is often called the Triangulum Galaxy. Sometimes referred to as the Pinwheel Galaxy, but that is the name given to Messier 101. It is the smallest spiral galaxy of our local group of galaxies stretching across 60,000 light years and containing some 40 billion stars.
The galaxy contains many interesting regions, one is the HII region given the name of NGC 604. It is one of the largest HII regions in the local group. Three other large HI regions are NGC 595, NGC 592, and NGC 588.
Several other open clusters and HI regions also exist and are given IC numbers. Also several other distant background galaxies are visible.
