Galaxies are perhaps one of the most attractive deep-sky objects to observe and photograph. They represent massive collections of dust, gas and countless billions of stars and are best described as islands of space matter across the universe. They are characterized as being either spiral or elliptical in nature and usually have a bright central core. Equally stunning to observe (with large-aperture telescopes) and image are galaxy clusters which represent collections of gravitationally-bound groups of galaxies whose members number from tens to thousands and which are classified on the basis of their richness (ie. number of galaxy members), shape (spherical, flat or irregular) and content (spiral or elliptical). Charles Messier's list of deep-sky celestial gems includes approximately forty bright and large galaxies.

Note: The stunning Pinwheel galaxy (M33, NGC 598) in Triangulum has the great distinction of perhaps being the most distant object visible with the naked eye. Lying at a distance of 2.75 million light-years away, M33 is one of the three large member galaxies of the Local Group having an apparent diameter which exceeds two full moons in diameter and which represents a physical diameter of 55,000 light-years across. The Pinwheel galaxy is a recognized source of H-II emission activity and many knots and regions have their own NGC and IC classifications as a result. No supernova have yet to be found in M33 but evidence exists for possible supernova remnants. This celestial gem was discovered by Hodierna around 1654 and later rediscovered by Messier in 1764. The Pinwheel galaxy is best observed during fall and winter when it is fairly high in the eastern sky.