NGC 56
NGC 56 is a New General Catalogue entry for a supposedly observed astronomical body that does not exist.[1][2] This object was recorded by John Herschel early in his observations as part of his 1825 "sweep 14." He recorded only that, "about this place a considerable space seems affected with nebulosity." Astronomers have noted that the observation may have been of a reflection of a bright star which lies two degrees to the north of NGC 56's location. The other recorded observations by John Herschel at this time included Messier 15, and were correctly located, so the error is not attributed to a general error in locating objects during the survey.[3]
This supposed object is located at R.A. 00h 15m 20.6s and Dec. +12° 26′ 40″.
A nearby galaxy that seems to fit the description is PGC 1107, but the galaxy is an entire magnitude fainter than most NGC objects, rendering it unlikely to have been seen by John Herschel.