NGC/IC Project Restoration Effort

===== NGC 2139 = IC 2154. Dreyer has a note in his 1912 edition of WH's Scientific Papers on this object. Taken from WH's note in the sweep, it reads "The A.R. cannot be above 10 or 15 s out; the roller went off the apparatus which occasions the uncertainty." The RA is actually 24 seconds out, and the dec, due to another unspecified error, is 8.5 arcmin off. Dreyer was further able to identify a star in the sweep that was closer to the galaxy than WH's "official" reference star, delta Canis Majoris. Comparison with this star led to the correct position. However, he had not yet done this when Howe and Bigourdan tried to find the NGC object near WH's place -- not surprisingly, neither succeeded. What is surprising is that when Lewis Swift came across the galaxy over a century after WH, he did not make as nearly as large an error in its position as WH. Swift's positions from his last nights in 1897 and 1898 at Lowe Observatory on Echo Mountain are nortoriously bad. But for this object, he actually came within 14 seconds in RA and 1 arcmin in Dec. Herbert Howe pinned the galaxy down with a micrometric observation and it was that position that Dreyer adopted for IC 2154. Dreyer himself discovered the identity when he fixed WH's position for the NGC object.

===== NGC 2139 17.5" (12/8/90): moderately bright, moderately large, slightly elongated, broad concentration, core appears offset to the northwest of center. A mag 14 star is at the north edge 1.3' from center and a mag 11 star lies 3.5' SSE. 8" (1/1/84): faint, fairly small, round, broad concentration. A mag 11 star is 4' SSE.