Guillaume Bigourdan discovered IC 139 = B. 129, along with numerous other HII regions and star clouds in M33, on 28 Oct 1889. See IC 135.

400/500mm - 17.5" (10/25/97): fairly prominent elongated HII region and star association just following a mag 13 star 5.4' SSE of the center of M33. Extended ~N-S, perhaps 2.0'x0.5' and consists of two brighter knots at both ends (the size appears too large). Similar view on 7/5/86.

Notes by Steve Gottlieb