NGC 2392, known as the Eskimo Nebula or Clown Face Nebula, is a planetary nebula visible with a small telescope in Gemini.
William Herschel discovered this planetary nebula in 1787 and cataloged it as H IV.45. John Herschel observed it from England in the 1820s, numbered it as h 450, and included it in the 1864 General Catalogue as GC 1532. It became NGC 2392 in J. L. E. Dreyer's New General Catalogue of 1888. Because of its double-shell morphology, this nebula was nicknamed the Eskimo or Clown Face Nebula: it resembles a person's head surrounded by a parka hood.
The nebula has a visual magnitude of 9.1, and is about about 40" in diameter. A modest telescope will show a small greenish ball and reveal the central star. The central star, HD 59088, is of spectral type O7f and visual magnitude 10.5, and thus seen quite easily. Its distance is not very well known, and estimated sometimes at some 3,000 light years.
In larger instruments, the Eskimo Nebula exhibits a fine luminous, bluish-colored disk divided by a concentric dark ring. The central portion is 15" across with a 10.4 magnitude central star. The faint 45" diameter outer shell surrounds the indistinct dark ring, which encircles the inner bright disk about halfway out from the nebula's center to its periphery.