John Herschel discovered NGC 3142 = h3232 on 5 May 1836 and recorded "F; vsbM to a * 16m; diam 1' or 1 1/2'; sp the star g Sextantis, which occasioned its being taken by mistake for Halley's Comet, and the consequent loss of that comet." His position matches MCG -01-26-028 = PGC 29586.

400/500mm - 17.5" (4/9/94): faint, very small, round, brighter core. Overpowered by 17 Sextantis (V = 5.9) 4.3' N. A second bright star 18 Sextantis (V = 5.6) lies 12.8' ENE.

Notes by Steve Gottlieb