The most distant object easily visible to the eye is M31, the great Andromeda Galaxy some two and a half million light-years away. But without a telescope, even this immense spiral galaxy - spanning over 200,000 light years - appears as a faint, nebulous cloud in the constellation Andromeda. In contrast, details of a bright yellow nucleus and dark winding dust lanes, are revealed in this digital telescopic image. In this image also a data recording emission from hydrogen atoms, shows off the reddish star-forming regions dotting gorgeous blue spiral arms and young star clusters. While even casual skygazers are now inspired by the knowledge that there are many distant galaxies like M31, astronomers seriously debated this fundamental concept in the 20th century. Were these "spiral nebulae" simply outlying components of our own Milky Way Galaxy or were they instead "island universes" -- distant systems of stars comparable to the Milky Way itself? This question was central to the famous Shapley-Curtis debate of 1920, which was later resolved by observations of M31 in favour of Andromeda, island universe.

Our Milky Way Galaxy is not alone. It is part of a gathering of about 25 galaxies known as the Local Group. Members include the Great Andromeda Galaxy (M31), M32, M33, the Large Magellanic Cloud, the Small Magellanic Cloud , Dwingeloo 1, several small irregular galaxies, and many dwarf elliptical and dwarf spheroidal galaxies. Pictured is one of the dwarf ellipticals: NGC 205. Like M32, NGC 205 is a companion to the large M31. The image shows NGC 205 to be unusual for an elliptical galaxy in that it contains at least two dust clouds (they are visible but hard to spot) and signs of recent star formation. This galaxy is sometimes known as M110, although it was actually not part of Messier's original catalog. [Text from APOD]