* Astronomy

NGC 1909 (also Witch Head nebula, IC 2118, LBN 959, and Cederblad 41) is a magnitude 13.7 reflection nebula located about 900 light-years away in the constellation Eridanus. The reflection nebula is considered to be very old supernova remnant illuminated by the nearby bright supergiant, Rigel, lying in the constellation Orion. The colour of the nebula comes not only from the star Rigel, but above all is the result of the scattering of light on the dust particles; the blue light is scattered more efficiently than red, and this is the main factor that gives the Witch Head of its blue colour.

The nebula was probably discovered by the German-British astronomer William Herschel using a 47.5 cm (18.7 inch) f/13 speculum reflector at Windsor Road, Slough, on the 20th December 1786 (In the original position noted by Herschel there is nothing, but it is speculated, that Herschel made a simple east-west directional mistake when calculating the position of the object relative to the star Rigel).
IC 2118 was rediscovered by Max Wolf on the 16th January 1891.

Radio observations show substantial carbon monoxide emission throughout parts of IC 2118 an indicator of the presence of molecular clouds and star formation in the nebula. In fact candidates for pre-main sequence stars and some classic T-Tauri stars have been found deep within the nebula
Read more

Right ascension 05h 02m 00.00s, Declination -07° 54' 00"