NGC 1535
NGC 1535, also known as Cleopatra's Eye, is a planetary nebula in the constellation of Eridanus, discovered by William Herschel on February 1, 1785. It is very similar to the Eskimo Nebula in both color and structure but the central star can be quite difficult to observe visually. The object is included in the Astronomical League's Herschel 400 Observing Program.
At the center of NGC 1535, there is an O-type star with a spectral type of O5.