NGC/IC Project Restoration Effort

===== NGC 3609 is also NGC 3612. Steve Gottlieb noticed that Otto Struve found this galaxy twice while searching for Comet Winnecke in the spring of 1869 at St. Petersburg. Struve's first observation came on 16 March 1869 and clearly refers to NGC 3609 -- but is listed in the NGC as "3612". The second observation comes from 18 March 1869 and describes the same galaxy. The positions are slightly different which misled both Struve and Dreyer into thinking that Struve had seen two galaxies here, while he had in fact seen only one. Here are Struve's observations: March 16 [1869]. alpha = 11h 10m 47s, delta = 27d 20m. Faint nebula about 30"-40" in diameter. Approximately 2 arcminutes north-following is a star (10. 11), from which the nebula is in position angle 225d. March 18 [1869]. alpha = 11h 10m 36s, delta = 27d 21m. Significantly brighter than the previous one [NGC 3534], 20" in diameter, with evident concentration towards the middle. Position angle from a 10th magnitude star = 226d. There are indeed two galaxies here, one about 25 seconds of time east of the first. However, that second galaxy is fainter, has a lower surface brightness, and -- in particular -- does not have the 10th-11th magnitude star two arcminutes to the northeast. Steve has also noticed that Struve's position for NGC 3534, mentioned in the second observation on the same night, is offset from the true position by -13 seconds of time, close to the -15 seconds that Struve's position for NGC 3612 is offset from the true position. (The other galaxy from the same night, NGC 3563, has a position offset of only 4 seconds, but in the same direction.) All of this makes it clear that Struve discovered the same galaxy twice. The preferred number, by the way, is NGC 3609.

===== NGC 3609 17.5" (4/22/95): faint, moderately large, round, 1.2' diameter. Weak concentration to a slightly brighter core. A mag 14 star is just off the south edge 50" from center and a second mag 14 star is 1.8' NW. A brighter mag 11 star lies 3.3' NE. Forms a pair with UGC 6321 (misidentified as NGC 3612 in modern sources) 5.4' E. UGC 6321 appeared extremely faint, small, round, 20" diameter, low surface brightness. A mag 11 star lies 3.9' NW.