NGC 2170 (also LBN 994 and Magakian 173) is a magnitude +10.2 reflection nebula located 2,700 light-years away in the constellation Monoceros. The nebula is lit by a magnitude +10.38 blue (spectral class B1) star, SAO 132861. The star is a member of Monoceros OB association. The nebula is located at about 3° west of the magnitude +3.99 giant orange star Gamma Monocerotis.
The nebula was discovered by German-British astronomer William Herschel using a 47.5 cm (18.7 inch) f/13 speculum reflector at Datchet, Berkshire, on the 16th October 1784.
Right Ascension 06h 07m 31.3s, Declination -06° 23' 53"
