The Ring Nebula (NGC 6720) was a planetary nebula in the constellation of Lyra.
An image of the nebula was on display on one of the large bridge monitors aboard the USS Enterprise in 2266 and 2267. (TOS: "Charlie X")
An image of the nebula, taken by the Hubble telescope, was on display in astrometrics aboard the USS Voyager in the year 2376. (VOY: "Alice")