NGC/IC Project Restoration Effort

===== NGC 6946 48" (10/23/11): this very bright, showpiece face-on spiral stretches roughly 9'x7' E-W. At 375x, four arms were visible, each containing one or more HII regions. The brightest arm is attached on the west side of the central region and curves counterclockwise to the north and then heads east, passing just south of a mag 13.5 star and spreads out to the NE of the central region. At the eastern tip (4.2' from center) is a bright HII knot of 12" diameter, catalogued as #3 under NGC 6946 in Paul Hodge and Robert Kennicutt's 1983 "Atlas of HII Regions in 125 Galaxies" (HK83-3) and #1 in Hodge's 1969 paper "HII regions in twenty nearby galaxies" (H69-1). A second shorter arm emerges from the core on the north side, and rotates more sharply around the galaxy on the north side, passing south of the brighter arm, and curving around to the east side. It contains HK83-63/76 = H69-6, an elongated knotty HII complex at its tip, 2.5' due east of center. On the west side are two additional arms, though the brighter inner arm is better defined. It begins on the south side of the central region and curls sharply to the north on the west side. It passes through a few mag 14 foreground stars and nearly fades out 3.2' NW of center. A dim extension finally ends 3.5' N of center at HK83-285 = H69-20, a very faint, very small knot inside a triangle of stars. An outer arm on the south side rotates towards the west and intersects HK83-503/507 = H69-33, a very bright, round knot of 20" diameter, that rivals the inner core in size. Using a DGM Optics "Galaxy Contrast" filter, the core was dimmed more and the knot appeared nearly as bright. Studies reveal this feature is a circular bubble containing numerous, tightly packed small clusters and a bright supermassive star cluster that resembles a young globular. After this point, the arm becomes more patchy as it spreads to the northwest, but near the end is HK83-527/528, an extremely faint knot just west of a mag 14 star 3.5' NW of center. 24" (9/13/12): the bright, long, outer spiral arm on the north side passes very close south of a mag 13.5 star before terminating near the small knot HK83-3 = H69-1. Besides the knot at the end, this arm is a bit clumpy with two slightly brighter regions roughly 1.7' N of center, HK83-213 = H69-11, and 2.4' NE of center, HK83-123/124 = H69-10. The spiral arm extending north on the west side has several mag 14 stars superimposed. A very small brighter nucleus is embedded the very broadly brighter central region. 18" (8/1/08): I took another look at the bright, circular knot that contains a young massive globular. This knot is located 2.8' WSW of the core of NGC 6946. It was fairly easy to identify using a pair of mag 13/13.5 stars [18" separation] with the cluster situated 1.5' NW of this fairly wide double. At 280x it appeared as a very faint, hazy glow, ~15" diameter (nearly the separation of an unequal double star to the southeast). 18" (7/31/05): using the photographic finder chart in the 2000 Astrophysical Journal (535,748) paper titled "A Young Globular Cluster in the Galaxy NGC 6946", I tracked down this "knot" which contains numerous star clusters as well as a 15 million year old supermassive star cluster or young globular. This object is located 2.8' W of the core and 1.5' NW of a wide, unequal pair of stars. On the DSS, it appears to be located near the end of a faint arm (not seen) that attaches to the core on the south side and extends to the west. Using the image, I quickly pinpointed the location and at 323x a very faint, small, roundish glow of ~15" diameter was visible. This very low surface brightness spot was visible 80-90% of the time with averted vision once identified and appeared similar to a faint Abell planetary. Without the finder chart, I would probably have passed over this object without noticing it, and in fact missed it in my observation from the White Mountains in 8/29/02. Using ALADIN, the position of the young globular is 20 34 31.7 +60 08 17. 18" (10/9/04): viewed type II supernova 2004e, discovered 9/27/04 (13 days ago) and appearing at approximately mag 12.8. It was easily identified using a photographic finder chart. The supernova is located 4.1' E and 1.9' S of the nucleus, just west of a pair of mag 13/13.5 stars at 12" separation and was comparable to the brighter star of this pair. A fainter mag 14.4 star is close WSW and the three stars plus supernova form a small wedge or Sagitta shaped group. This is the 8th supernova discovered in NGC 6946 since 1917. NGC 6939 and 6946 were both easily visible in 15x50 IS binoculars and of similar size, but NGC 6939 is brighter with a higher surface brightness. 17.5" (8/29/92, White Mountains at 12,000 ft): bright, very large, 6' diameter to main body, elongated 3:2 ~E-W. Three arms are visible. A long bright arm is attached at the north side of the core and trails to the east. This eastern arm splits; a short fainter branch bends south following the core and a long curving bright arm terminates with a very faint, very small HII knot HK83 #3. On the west side a fainter arm shoots sharply to the north from the core. These outer arms significantly increase the diameter of the main body. The galaxy has a very large brighter middle but the core is just a very small brighter region close SW of the geometric center. A very faint stellar nucleus was seen with direct vision. 17.5" (8/13/88): main spiral arm very prominent and easily seen to split. 17.5" (9/14/85): bright, large, brighter central core. A prominent arm attached on the NE side of the core and trailing to the east. This arm splits - the shorter arm is close to the core and a brighter region or arm to the west. 13.1" (7/27/84): bright arm on the east side highly suspected to branch or split into two arms. Also an arm or brighter region seen on the opposite side of the galaxy pointing west a short way. 13.1" (7/16/82): the central region is elongated and fairly low surface brightness though a spiral arm clearly trails off to the east from the main body creating a non-symmetrical appearance. 8" (6/22/81): faint, large, diffuse, brighter core. Situated in a rich star field.