NGC 6946

Right Ascension	20 : 34.8 (h:m)
Declination	+60 : 09 (deg:m)
Distance	10,000 (kly)
Visual Brightness	8.9 (mag)
Apparent Dimension	11 x 10 (arc min)

Discovered by William Herschel in 1798.

8.9-mag NGC 6946 was discovered by William Herschel on September 9, 1798.

NGC 6946 is a rather nearby spiral galaxy, which at one time was suspected to be an outlying member of the Local Group (Hubble 1936). It is highly obscured by interstellar matter of the Milky Way galaxy, as it is quite close to the galactic plane.

Eight supernovae have been detected in NGC 6946 as of this writing (December 2004):

• SN 1917A occurred on July 19, 1917 when it was discovered by Ritchey. This supernova, situated 37"W and 105"S of the galaxy's nucleus, lightened up to 14.6 mag.
• SN 1939C was discovered by Fritz Zwicky on July 17, 1939 (see IAU Circular No. 793), 215"W and 24"N of the galaxy's center, and peaked at 13.0 mag.
• SN 1948B was found by Mayall when it flashed up on July 6, 1948, 222"E and 60"N of the galaxy's nucleus; it reached magnitude 14.9 (see IAUC 1161)
• SN 1968D brightened up on February 29, 1968 the leap day, 45"E and 20"N of the galaxy's center, and became as bright as 13.5 mag. This supernova was discovered by Wild and Dunlap, and was found to be of type II (see IAUC 2057 and IAUC 6045)
• SN 1969P occurred on December 11, 1969, 5"W and 180"S of the nucleus and reached mag 13.9. It was found by Rosino (see IAUC 2305)
• SN 1980K was discovered by Wild on October 28, 1980 when it occurred 280"E and 166"S of the galaxy's center; it reached mag 11.4 (see IAUC 3532 and AJ 111, 2017)
• SN 2002hh, of type II, was discovered by the LOTOSS project (W. Li) on unfiltered KAIT images taken on Oct. 31, 2002, 60".9 west and 114".1 south of the nucleus of NGC 6946 at about 16.5 mag, and reached about mag 15.0 at its maximum.
• SN 2004et, another type II supernova, was found by Stefano Moretti in the evening of September 22, 2004, located 247".1 east and 115".4 south of the nucleus of NGC 6946 when it was at a brightness of 12.8 mag. It peaked at 12.3 mag on September 30, 2004.

In the SAC 110 best NGC object list. In the RASC's Finest N.G.C. Objects Objects list. Caldwell 12 in Patrick Moore's list.

NGC Online data for NGC 6946

References

• Edwin P. Hubble, 1936. The Realm of the Nebulae, Yale University Press.

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Hartmut Frommert
Christine Kronberg
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Last Modification: December 8, 2004