M33 has a diameter of about 60,000 light-years, about 60% the size of our own Milky Way.   It is a spiral galaxy approximately 3 million light years from Earth, located in the constellation Triangulum. It is third largest member of the galactic Local Group, behind Andromeda and our own Milky Way.  Like Andromeda, it can be viewed with the naked eye under sufficiently dark conditions. 

Scientific studies have revealed several streams of neutral hydrogen and stars between Andromeda and Triangulum, suggesting the two may have interacted some 2 to 8 billion years ago.   Thus, it may be gravitationally bound to Andromeda and possibly be consumed by its larger neighbor in the future.

Some amateur references incorrectly refer to Triangulum as the “Pinwheel Galaxy”, which is the moniker more traditionally applied to Messier 101.

Charles Messier discovered the object on the nights of August 25-26, 1764, being 33rd in his Catalog of Nebulae and Star Clusters.  However, Italian astronomer Giovanni Battista Hodierna was likely the first to identify the galaxy sometime before 1654.   His work De systemate orbis cometici describes a cloud-like nebulosity near the triangle hinc inde.

Acquisition Details

Frames: 21 Red, 21 Green, 21, Blue, 21 Lum, 2.8 Hours Integration
Calibration: Full Bias, Dark, and Flat calibration
Equipement: Orion 130mm Refractor, Atik 383L+