NGC/IC Project Restoration Effort
(This is a very very beta version)
Location and Magnitude
Right Ascension: 4:44:23.5
Visual Magnitude: 12.4
Discoverer: Herschel W.
Year of discovery: 1786
Discovery aperture: 18.7
Summary description: F, vS, iR, bM, * 7 np
NGC 1646 has a companion seen by R.S. Ball with LdR's 72-inch reflector at
Birr Castle. The story is in the "notngc" files.
24" (12/21/16): at 432x; moderately bright, fairly small, slightly elongated, ~NNW-SSE, 0.4'x0.3', high surface brightness, contains a very small bright nucleus. With averted vision a very low surface brightness halo increases the size to roughly 40"x25" NNW-SSE. Occasionally an extremely faint stellar or quasi-stellar object briefly popped on the SSE edge of the halo. This is nucleus of a merged companion NGC 1646 NED2, just 15" between centers of the nuclei! The stellar companion (perhaps a faint star?) was seen more often with confidence (though not continuously) through Bob Douglas's 28" at 439x. NGC 1646 is located 4.8' ESE of 5.9-magnitude 56 Eridani, which needs to be kept outside the field! A mag 10.5 star is 2' E and a mag 14.7 star is 0.9' S.
17.5" (1/23/93): fairly faint, small, elongated 2:1 NW-SE, prominent small bright core, overall fairly high surface brightness. Forms the south vertex of isosceles triangle with NGC 1648 4.4' NE and 56 Eridani (V = 5.9) 4.8' WNW. The bright star detracts from viewing! A mag 11 star lies 2.1' E.