NGC 747
Galaxy in the constellation Cetus
From Wikipedia, the free encyclopedia
NGC 747 is a spiral galaxy located in the constellation Cetus.[1] Its speed relative to the cosmic microwave background is 5,100 ± 19 km/s, which corresponds to a Hubble distance of 75.2 ± 5.3 Mpc (~245 million ly).[2] NGC 747 was discovered by American astronomer Francis Leavenworth in 1886.[3] The luminosity class of NGC 747 is II and it has a broad HI line.[4] To date, four non-redshift measurements yield a distance of 83.900 ± 4.166 Mpc (~274 million ly), which is within the Hubble distance range.[5] Note, however, that it is with the average value of independent measurements, when they exist, that the NASA/IPAC database calculates the diameter of a galaxy and that consequently the diameter of NGC 747 could be approximately 23 .9 kpc (~78,000 ly).[6] In the same area of the sky there are, among other things: the galaxies NGC 713, NGC 731, NGC 755 and NGC 767.
| NGC 747 | |
|---|---|
| |
| Observation data (J2000 epoch) | |
| Constellation | Cetus |
| Right ascension | 01h 57m 29s |
| Declination | -09° 27′ 45″ |
| Redshift | 0.0179 |
| Apparent magnitude (B) | 14 |
| Surface brightness | 23.05 mag/arcsec2 |
| Other designations | |
| PGC 7366, 2MASX J01573044-0927444, MCG -02-06-007, SDSS J015730.45-092744.5 | |