Pinwheel Galaxy
The Pinwheel Galaxy (also known as Messier 101, M101 or NGC 5457) is a face-on spiral galaxy 21 million light-years (6.4 megaparsecs) from Earth in the constellation Ursa Major. It was discovered by Pierre Méchain in 1781 and was communicated that year to Charles Messier, who verified its position for inclusion in the Messier Catalogue as one of its final entries.
| Pinwheel Galaxy | |
|---|---|
The Pinwheel Galaxy, as taken by Hubble Space Telescope | |
| Observation data (J2000 epoch) | |
| Constellation | Ursa Major |
| Right ascension | 14h 03m 12.6s |
| Declination | +54° 20′ 57″ |
| Redshift | 0.000804 |
| Heliocentric radial velocity | 241 ± 2 km/s |
| Distance | 20.9 ± 1.8 Mly (6.4 ± 0.5 Mpc) |
| Apparent magnitude (V) | 7.9 |
| Characteristics | |
| Type | SAB(rs)cd |
| Number of stars | 1 trillion (1012) |
| Size | 51.91 kpc (169,300 ly) (diameter; 25.0 mag/arcsec2 B-band isophote) |
| Apparent size (V) | 28′.8 × 26′.9 |
| Other designations | |
| Messier 101, M101, NGC 5457, UGC 8981, PGC 50063, Arp 26 | |
References: | |
On February 28, 2006, NASA and the European Space Agency released a very detailed image of the Pinwheel Galaxy, which was the largest and most-detailed image of a galaxy by Hubble Space Telescope at the time. The image was composed of 51 individual exposures, plus some extra ground-based photos.
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