When we look away from the galactic disk, we see into the great beyond of intergalactic space. This is the Realm of the Galaxies, gracing our evening skies in spring and fall. Long time exposure photography through a telescope reveals innumerable galaxies in every direction in these parts of the sky.
Galaxies were called “island universes” when they were discovered in the early years of telescopes. Many are the familiar spirals like our Milky Way. Others are formless blobs called ellipticals or irregulars, often formed by the mergers of smaller galaxies. Our Milky Way contains hundreds of billions, perhaps as many as a trillion stars.
Only three galaxies are easily seen with the naked eye from the darkest places on Earth: the Andromeda Galaxy covers an area six times the size of the full Moon; and the two Megellanic Clouds can be seen only from deep in the Southern Hemisphere. Dozens are visible in binoculars if you know where to look. It takes a large telescope to see spiral structure in many galaxies, but their true nature is only seen with long time exposure photography.
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| M33 in Triangulum, imaged from Fort Collins CO |