Harold Corwin

IC 1765 = NGC 783 and IC 1766 = NGC 785. Barnard's positions -- particularly the RA's -- are poor enough that he was misled into thinking them new nebulae. He must have sent them in a letter to Dreyer as there is no reference to Barnard's published papers in the IC entries, nor can I find them in my copies of Barnard's papers that I've collected.

Nevertheless, the identifications are quite certain. The position difference between the galaxies is 33.4 seconds in RA and 3 arcmin 20 arcsec in Dec. Barnard's positions are 33 seconds in RA and 4.1 arcmin in Dec in the correct orientation: IC 1766 is to the southeast of IC 1765. The differences for the NGC objects is 34 seconds and 3.3 arcmin (from Stephan's observations). Assuming that Barnard observed the galaxies on the same night and measured their positions in the same way, the agreement with the actual differences is compelling evidence that Barnard's "novae" are actually the NGC objects.

Reinmuth was the first to suggest the identities. Carlson picked them up for her 1940 ApJ collection, and the CGCG has them both, too. Curiously, Wolfgang has only the I1765/N783 identity in his list. He puts the number IC 1766 on a very faint, low-surface-brightness galaxy that Barnard almost surely could not have seen, even if he found the galaxies with the 36-inch or 40-inch refractors.

― IC Notes by Harold Corwin

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