Spiral Galaxy NGC 6946 in Cepheus

This image is a combined effort with Chris Deforeit of France. The Luminance data is a 9-minute exposure with ST-9E camera thru Kopernik's 20-inch F/8.1 telescope. The color data is from three 10-minute exposures taken with ST-8 camera thru Chris Deforeit's 18-inch F/2.8 telescope.

Supernova 2004et:

• Discovered by Stefano Moretti of Italy on Sept. 29, 2004.
• A Type II supernova discovered before max brightness.
• Measures red magnitude 12.65 and blue magnitude 13.40 in the Kopernik image taken at 6:10 UT on Oct. 13, 2004.

Spiral Galaxy NGC 6946:

Quote from the Deep Sky Field Guide to Uranometria 2000:

"Extremely small, bright nucleus, three or four main massive arms with much branching, low surface brightness (14.2). Emission patch 4.1 arc minutes NE of nucleus."

Discovered by William Herschel in 1798, NGC 6946 is a face-on spiral galaxy in that has an H II region nucleus and several massive and branching spiral arms. It is among the closest galaxies to the Local Group, being about 4 times further than M-31, the Andromeda Galaxy. It has had eight recorded supernovae, the most of any galaxy. There are also a total of 27 additional known supernova remnants in this system. The Hubble Space Telescope has observed two of these supernova remnants colliding with each other!

• NGC 6946
• Magnitude: 9.9
• Constellation: Cepheus
• RA: 20h 34m 51.9s
• Dec: +60° 09' 15" Epoch 2000
• Size (mins): 11.4' x 9.8'
• Classification: SAB(rs)cd I-II
   Spiral, Mixed Barred/Non-barred, Mixed S-shaped/Ring structure, Luminosity Class I-II
  
  

Click below to

George Normandin, KAS

October 15th, 2004