Spiral galaxy M33 in Triangulum
author: IAC/RGO/David Malin Images/Novapix
reference: a-gax05-98013
Image Size 300 DPI: 22 * 28 cm
M33 is a large, almost face-on spiral galaxy about 2.5 million light years distant in the northern constellation of Triangulum. It is a member of the 'Local Group' of galaxies, which is dominated by the Milky Way and M31. Like M31, M33 is approaching the Milky Way at a velocity of about 180km/s. Though the total light M33 galaxy is that of a star of magnitude 5.3, its large diameter makes it hard to see. However, despite its low surface brightness, this galaxy was among the first to be identified as a 'spiral nebula' by Lord Rosse in the 1840s. On shorter exposures, the nucleus appears very bright and almost stellar, like that in its southern cousin, NGC 300.