| NGC 945 | |
| Epoch: | J2000 |
| Appmag B: | 1202h 28m 36s |
| Dec: | -10° 32 20 |
| Ra: | 02h 28m 36s |
| Sbrightness: | 23.01 mag/arcsec2 |
NGC 945 is a barred spiral galaxy in the constellation Cetus,[1] located south of the celestial equator. It is estimated to be 200 million light-years from the Milky Way, and about 135,000 light-years in diameter.[2] The object was discovered by astronomer William Herschel on November 28, 1785. It is within close proximity to NGC 948, with which it forms a gravitationally bound pair of galaxies. In the same area of the sky there are the galaxies NGC 942, NGC 943, NGC 950, and IC 230.
NGC 948 is a spiral galaxy located extremely close to NGC 945.[3] Its speed relative to the cosmic microwave background is 4,259 ± 17 km/s,[4] which corresponds to a Hubble distance of 62.8 ± 4.4 Mpc (~205 million ly). NGC 948 was discovered by American astronomer Lewis Swift in 1886. The luminosity class of NGC 948 is III and it has a broad HI line. With a surface brightness equal to 14.17 mag/am2, NGC 948 is classified as a low surface brightness galaxy (LSB).[5]
Two supernovae have been observed in NGC 945. SN1998dt was discovered in NGC 945 on September 1, 1998, by T. Shefler of the University of California at Berkeley[6] as part of the LOSS (Lick Observatory Supernova Search) program at the Lick observatory. This supernova is classified as a type Ib.[7] SN2020obd (typeII, mag. 17.3) was discovered on 6 July 2020.[8]
NGC 945 is the brightest galaxy in a group of at least 7 members that bears its name.[9] The other six galaxies in the NGC 945 group are NGC 948, NGC 950, NGC 977, MCG -2-7-20, MCG -2-7-32 and MCG -2-7-337.