NGC 891
| NGC 891 | |
|---|---|
Spiral Galaxy NGC 891
|
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| Observation data (J2000 epoch) | |
| Constellation | Andromeda |
| Right ascension | 02h 22m 33.4s |
| Declination | +42° 20′ 57″ |
| Redshift | 528 ± 4 km/s |
| Distance | 27.3 ± 1.8 Mly (8.4 ± 0.5 Mpc) |
| Apparent magnitude (V) | 10.8 |
| Characteristics | |
| Type | SA(s)b? |
| Apparent size (V) | 13′.5 × 2′.5 |
| Other designations | |
| UGC 1831, PGC 9031,Caldwell 23 | |
NGC 891 (also known as Caldwell 23) is an edge-on unbarred spiral galaxy about 30 million light-years away in the constellation Andromeda. It was discovered by William Herschel on October 6, 1784. The galaxy is a member of the NGC 1023 group of galaxies in the Local Supercluster. It has an H II nucleus.
The object is visible in small to moderate size telescopes as a faint elongated smear of light with a dust lane visible in larger apertures.
In 1999, the Hubble Space Telescope imaged NGC 891 in infrared.
In 2005, due to its attractiveness and scientific interest, NGC 891 was selected to be the first light image of the Large Binocular Telescope. In 2012, it was again used as a first light image of the Discovery Channel Telescope with the Large Monolithic Imager.
Supernova SN 1986J was discovered on August 21, 1986 at apparent magnitude 14.
NGC 891 looks as the Milky Way would look like when viewed edge-on (some astronomers have even noted how similar to NGC 891 our galaxy looks as seen from the Southern Hemisphere) and in fact both galaxies are considered very similar in terms of luminosity and size; studies of the dynamics of its molecular hydrogen have also proven the likely presence of a central bar. Despite this, recent high-resolution images of its dusty disk show unusual filamentary patterns. These patterns are extending into the halo of the galaxy, away from its galactic disk. Scientists presume that supernova explosions caused this interstellar dust to be thrown out of the galactic disk toward the halo.
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Wikipedia