NGC 6946 Fireworksgalaxy

Barred spiral galaxy in the constellation Cepheus

NGC 6946 or Arp 29 or Fireworks Galaxy is a Hubble-type SAB(rs)cd barred spiral galaxy in the constellation Cepheus at the boundary of the constellation Cygnus in the northern starry sky.

NGC 6946
Please click on the image for a bigger view.
Object: NGC 6946
Date of exposures: 17.07.2021, 22.07.2021, 29.07.2021, 10.08.2021
Distance: 21 Mio. Lightyears
Exposures: Luminance: 67 x 180", RGB: 205 x 180", Sum: 13,5 hrs
Telescope: 10'', F4 Newton
Focal length: 1000 mm
Filter: Astrodon LRGB E-Series
Camera: ASI 1600 MMC Pro
Guiding: Off Axis Guider, Lodestar
Mount: EQ8

The galaxy is close to our galactic plane, so the light coming to us from NGC 6946 is strongly obscured by gas and dust from our galaxy. This makes it difficult to photograph this galaxy and its members, and especially to determine their distance. In particular, from the supernova observations their distance should be determined, for which besides the apparent brightness and the absolute brightness also the interstellar extinction must be known.

Here is a crop of the original field:


A calculation published in 1997 gave a photometric distance of 6.4 megaparsecs (21 million light years). Other measurements gave values between 4.1 and 10.5 megaparsecs. NGC 6946 leads the statistics of supernova frequencies in the last hundred years with a number of ten.

I myself could photograph the last supernova (2017eaw) also with a few frames:

Supernova NGC6946