IC 3138 lies a distance of 1.2 billion l.y. but IC 3137 is 4 times closer.

Royal Frost discovered IC 3138 = F. 859, along with IC 3137, on a plate taken on 7 May 1904 at Harvard's Arequipa Observatory in Peru. He described it as "R, bM, magn. 15.5."

900/1200mm - 82" (5/5/19, McDonald Observatory): at 400x; fairly faint, fairly small, slightly elongated SW-NE, 15"x12". A mag 17.0 star is off the SW edge. Forms a pair with IC 3137 1.5' NNW.

Notes by Steve Gottlieb