William Herschel discovered NGC 3842 = H III-378 = h962 on 26 Apr 1785 (sweep 402) and recorded "two [with III-377 = NGC 3837], the time and NPD is that of the most north [NGC 3842], which is the largest and brightest; and is vF, pS. The most south NGC 3837] eF; vS, but twilight is too strong to determine them properly." His position is 10 tsec preceding NGC 3842, so the identification is certain.

John Herschel misassigned H. III-377 to h962 and H. III-378 to h966 = NGC 3851 in the GC and Dreyer repeated this in the NGC. According to Harold Corwin, Bigourdan discovered nearby CGCG 097-090 = Big 47 (1' west), but it wasn't assigned a NGC or IC designation. MCG reverses the identifications of NGC 3841 and NGC 3842.

300/350mm - 13.1" (2/25/84): moderately bright, moderately large, bright core, many companions.

400/500mm - 17.5" (2/20/88): moderately bright, fairly small, round, small bright core. A mag 15 star is 0.8' SE of core. Brightest and largest in core of the rich cluster AGC 1367 with NGC 3841 1.3' N, UGC 6697 3.2' WNW, NGC 3845 2.9' NNE, NGC 3837 3.6' SSW and NGC 3851 4.7' ENE.

Notes by Steve Gottlieb