NGC 6946
| NGC 6946 | |
|---|---|
Spiral Galaxy NGC 6946
|
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| Observation data (J2000 epoch) | |
| Constellation | Cepheus & Cygnus |
| Right ascension | 20h 34m 52.3s |
| Declination | +60° 09′ 14″ |
| Redshift | 0.000160 |
| Helio radial velocity | 48 ± 2 km/s |
| Distance | 22.5 ± 7.8 Mly (6.9 ± 2.4 Mpc) |
| Apparent magnitude (V) | +9.6 |
| Characteristics | |
| Type | SAB(rs)cd |
| Apparent size (V) | 11.5 x 9.8 arcmin |
| Other designations | |
| UGC 11597, PGC 65001, Arp 29,Caldwell 12 | |
NGC 6946 (also known as the Fireworks Galaxy, Arp 29, and Caldwell 12) is an intermediate spiral galaxy about 22 million light-years away, in the constellations Cepheus and Cygnus. It was discovered by William Herschel on September 9, 1798. NGC 6946 is highly obscured by interstellar matter of the Milky Way galaxy, as it is quite close to the galactic plane. The diameter of the galaxy is approximately 40,000 light-years or just about a third of the size of the Milky Way. In the past century, nine supernovae have been observed to explode in the arms of this galaxy, which has been classified as a starburst galaxy. Chandra Space Telescope observations have, in fact, revealed three of the oldest supernovae ever detected in X-rays, giving more credence to its nickname of the "Fireworks Galaxy". This composite image also includes optical data from the Gemini Observatory in red, yellow, and cyan.
Nine supernovae have been observed in NGC 6946 in the last 100 years: SN 1917A, SN 1939C, SN 1948B, SN 1968D, SN 1969P, SN 1980K, SN 2002hh, SN 2004et, and SN 2008S. This makes it the most prolific known galaxy for this type of event over a period of 100 years. By comparison, the Milky Way galaxy, which has double the number of stars as NGC 6946, averages one supernova event per century. It also contained the failed supernova potential blackhole forming star N6946-BH1.
Coordinates: 
20h 34m 52.3s, +60° 09′ 14″
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