M33 is the third biggest galaxy of the Local Group after the Great Andromeda Galaxy (M31) and the Milky Way with a true diameter of 50'000 light years and a distance of 3 million light years.
William Herschel catalogued the brightest and largest HII region (lower right of the center) as NGC 604, with a diameter of about 1500 light years, roughly 50 times bigger than the Orion Nebula (M42).
This image is dedicated to my friend Daniel Marquardt, who passed away on the November 22nd, 2009. Together, we took a widefield image in fall 2008.
