NGC 3639 (also UGC 6374, MCG 3-29-36, GWT 96.32, ARAK 289 and PGC 34819) is a magnitude +13.7 face-on spiral galaxy located 250 million light-years away in the constellation Leo.
The galaxy was discovered by Irish astronomer R. J. Mitchell, assistant to William Parsons, 3rd Earl of Rosse, using a 182.88 cm (72 inch) speculum reflector at Birr Castle on the 21st January 1855.
Right Ascension 21h 11m 35.5s, Declination +18° 27' 31"
