Orion was the name of a constellation which was light years from Earth in the Mutter's Spiral galaxy.
Astronomical Data
Orion was in Mutter's Spiral. Though constellations typically contained stars hundreds of light-years apart, Orion was typically used to discuss a specific group of star systems. Once such member was the double star system known as Bellatrix.
History
The Osirian race placed great importance on the constellation. (MA: Sands of Time)
In the 26th century, Orion was settled by androids fleeing from persecution in the Earth Empire. They set up an independent society that demanded any humans in their territory must accept android rule or get out. The Earth Empire could not abide the restriction, and waged the Orion War in retaliation. (BFA: Sword of Orion, Cyberman)
Alternate Timelines
In Donna's World created by the Fortune Teller, the stars in the Orion constellation burnt out as a result two universes colliding. This event was observed by Wilfred Mott through his telescope. (DW: Turn Left')