NGC 6946 (UGC 11597, Arp 29) Galaxy in Cygnus

Located at: RA 20 hours 34 minutes 52 seconds; Dec +60 degrees 09 minutes 15 seconds

Size: 11.6' x 9.8' Magnitude: 9.6 blue Class: SAB(rs)cd HII

North is up

West to the right

Telescope:

 14.5" f5 Newtonian reflector

Camera:

 ST-8XME, self-guided, binned 1x1, temp -15c, camera control MaxIm DL 4.56

Image:

Lumicon Red filter, 640 minutes (64 x 10 minute subs), 07/3/4/5/6/2013; seeing 2.8-3.8 FWHM per CCDStack

Processing:

CCDStack 2.73.4932.15602, Photoshop CS5.1

Location:

 Rolling Roof Observatory, Thousand Oaks, CA 91360 (+34d 13m 29s -118h 52m 20s)

Notes:

NGC 6946 is just under 40 minutes SSE of the rich open cluster NGC 6939 (8" version). See the 8" version of NGC 6946.

From the NGC / IC Project:

Contemporary Visual Observation(s) for NGC 6946

NGC 6946 = UGC 11597 = MCG +10-29-006 = CGCG 304-006 = Arp 29
20 34 52.3 +60 09 14
V = 08.8;  Size 11.5x9.8;  SB = 13.8

18" (10/9/04): viewed type II supernova 2004e, discovered 9/27/04 (13 days ago) 
and appeared 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 of Sagitta shaped 
group.  This is the 8th supernova discovered in N6946 since 1917.

17.5" (8/29/92): 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.  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.  Observation from 
12,000' in the White Mountains.

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 arms splits - the 
shorter arm is close to the core and a brighter region or arm to the west.

13" (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 W a short way.

- by Steve Gottlieb