Deep-Space Photos: Hubble's Greatest Hits

The Hubble Telescopes Greatest Hits
The legendary space telescope celebrates its 20th year in orbit
NASA

Horsehead Nebula
Located approximately 1,500 light-years from Earth in the constellation Orion, this dark nebula is one of the most photographed and identifiable nebulae; its cloud dust and gases form what appears to be a horsehead in the night sky.

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