NGC/IC Project Restoration Effort

===== NGC 577 = NGC 580. Tempel claims to have found two nebulae 2m 50s following NGC 560 and 564, a pair found by WH. There is only one here, and it was also picked up by Swift in 1886 (more below) and, even earlier on 23 October 1867, by A. N. Skinner at Dearborn Observatory (see IC 1528 for that story). Tempel's position for it, apparently from a letter to Dreyer -- the position in his first paper on nebulae is about two arcmin off the NGC position -- is not bad. In particular, the NGC RA is less than two seconds of time off. Curiously, Dreyer also credits Tempel's second paper for this first nebula. I find no mention of it there, so suspect that Dreyer simply noted the wrong paper number. I'll check the rest of Tempel's papers to see if it is in fact mentioned in any of them. The second of Tempel's nebulae is probably one of the stars in the area, but since he gives the position with a precision of only 10 seconds of time and 10 arcminutes, we have little hope of recovering his object (Dreyer adopted Swift's position for this object). There are two stars northeast of the galaxy, though, that are similar in brightness to others that Tempel mistook for nebulae (see e.g. NGC 4315 and NGC 4322). One is at 01 28 12.05, -02 13 01.0; and a second somewhat brighter star is at 01 28 19.78, -02 12 20.3 (both positions are for equinox B1950.0). As I mentioned above, Swift also picked up the galaxy, on the night of 20 November 1886. Since he made his RA 23 seconds larger than Tempel's, Dreyer believed that this was the second of Tempel's nebulae. So, he adopted Swift's position. Howe corrected the RA in an observation in 1898, but neither he nor Dreyer, who published the correction as an IC2 Note, noticed that that made Swift's object, NGC 580, identical to NGC 577. Some observers might want to put one of these numbers onto one of the stars I've noted. But that number would be the following of Tempel's two, the one with the imprecise position -- and that is the one that Dreyer used for Swift's object. And we do not know for sure which star, if either, is the one seen by Tempel. So the easiest, and still a truthful, solution is to simply say that Tempel's one real nebula is identical to Swift's.

===== NGC 577 17.5" (9/26/92): faint, fairly small, slightly elongated 4:3 NW-SE, weak concentration, occasionally a very faint stellar nucleus is visible. Located near the east edge of AGC 194 and 5' WSW of a mag 10 star.