NGC/IC Project Restoration Effort

===== NGC 1491 is a diffuse nebula found by WH. His description is very good, as is his position. Dreyer nevertheless used the micrometric position measured by Engelhardt. This is refers to a star about 1.5 arcmin east of the brightest part of the nebulosity; WH mentions the star explicitly: "... a pL star in it towards the following side, but unconnected." The position I've adopted follows WH, and applies to the center of the nebula.

===== NGC 1491 18" (1/20/07): at 115x and 174x and OIII filter appears as a bright, large, elongated HII region on the west side of an 11th magnitude star. Appears roughly 4'x2', extending SSW to NNE and brighter on the south end. The west side has a fairly hard, well-defined edge while the east side is more irregular and fades into the background. Four faint stars are involved on the northern end and a pair of fainter stars are at the south end. 17.5" (3/2/02): at 100x, this is a moderately bright, roundish glow, ~3' diameter. ÊExtends mostly west of a mag 11 star, wrapping around the star, particularly on the north side. ÊExcellent contrast gain with an OIII filter as it appears bright with an irregular surface brightness. ÊThere is a subtle bite cut out of the nebulosity on the east side that creates a darker hollow extending just west of the star. ÊAt 220x (unfiltered), about a half dozen stars are involved or at the edges. ÊThe nebulosity is quite irregular with a high surface brightness region preceding the star. ÊFaint, elongated haze extends from this patch to the NE past the star giving an elongated appearance. ÊA pair of mag 13-14 stars is at the northern end and another pair is just off the western edge. 17.5" (12/8/90): at 140x with OIII filter appears as a bright, moderately large, circular nebulosity involving a mag 11 star. The brightest portion lies to the west of the star and is elongated 3:2 ~N-S. There appears be a dark gap just west of the mag 11 star. Two very faint stars are superimposed near the edges. 13" (1/18/85): bright emission nebula just west of a mag 10.5 star, extends SW-NE, interesting shape. 8" (11/14/80): bright, large, ~6' diameter. A mag 10.5 star is at the east side.