Tulip Nebula (Cederblad 173, Sh 2-101)
History
In 1946 the Swedish astronomer Sven Cederblad published a study of bright diffuse galactic nebulae where he listed this nebula as Cederblad 173. He noted: «BD +34°3828 nebulous. Source: (93 Pl 43). WP 154. (715). R. The star responsible for the nebular light is stated to be BD +34°3828 (93). Then, BD +34°3830 = HD 189688 (spectrum K5) would only be aligned with the nebula.» [130]
In 1953 the American astronomer Stewart Sharpless published his first survey for H II regions on the 48 inch Schmidt telescope photo plates of the «Palomar Observatory Sky Survey». This nebula was listed as Sh 1-75. [309] In 1959 he published a revised and extended version of his survey and listed this nebula as Sh 2-101. [310]
In 1955 the Russian astronomers Grigory Abramovich Shajn and Vera Fedorovna Gaze at the Simeis Observatory on the Crimean Peninsula published their Gaze-Shajn catalogue of emission nebula. Cederblad 173 was there listed as Gaze-Shajn 175. [402]
In Beverly Lynds «Catalogue of Bright Nebulae», which was published in 1965, this nebula is listed as LBN 71.58+02.86. Because it was the 168th entry in the list, the nebula is also referred to as LBN 168. [270]
As the nebula appears in photographs like the bloom of a tulip, it earned the nickname «Tulip Nebula.»
Physical Properties
Finder Chart
The nebula Sh 2-101 is located in the constellation Cygnus. The best time for observation is from March to December.
