Williamina Fleming discovered IC 2105 = HN 84 on Harvard objective prism plates. It was included in a 1901 table "Objects having peculiar spectra" (ApJ, 14, 144-146), based on its emission spectra. Robert Innes, observing in 1926 with the 26.5-inch refractor at the Union Observatory, noted "20 arc second diameter, resolvable". He added about 15 seconds preceding [should read following] this is a small faint and nebulous patch." The nebulous patch is part of LMC-N77.

600/800mm - 30" (11/6/10 - Coonabarabran, 264x): bright, small, round, compact, high surface brightness, 25" diameter. A mag 10.3 star lies just 0.6' NW of center. Located 5.5' SSE of cluster NGC 1698. The NGC 1727 complex (LMC-N79) lies ~17' SE. IC 2105 is the brightest knot in the LMC-N77 complex, mostly visible as very faint haze to the east.

Notes by Steve Gottlieb