NGC 891, Silver Sliver Galaxy

NGC 891
NGC 891: Edge-On Silver Sliver Galaxy NGC 891 in Andromeda; 500 mm Cassegrain f=3625 mm f/7.2; SBIG STL11K; 310+40+40+40 min LRGB; Bernese Highlands; © 2015 Radek Chromik

History

This galaxy was discovered, as is so often the case, by Wilhelm Herschel on October 6, 1784 with his 18.7 inch reflector telescope with a focal length of 20 feet. He entered it as V 19, the class «V» standing for very large nebulae. He described it as follows: «Considerabbly bright, much elongated, above 15' length 3' width, a black division of 3' or 4' length in the middle» [463] John L. E. Dreyer added the galaxy as NGC 891 in his «New General Catalogue of Nebulae and Clusters of Stars». [313] Because of its appearance, it has received the nickname «Silver Sliver» in the English-speaking world.

Physical Properties

NGC 891
NGC 891: Image taken with Hubble Space Telescope [261]

We see the galaxy NGC 891 directly from the edge, similar to NGC 4565 in the constellation Coma Berenices. Noticeable is the dense band of dust in the middle. You think you are looking at a miniature version of our Milky Way. In fact, both galaxies are very similar both in appearance and size, which is particularly evident in the HST image in Fig. 2. The galaxy is of the type SA(s)b? Whereby the «b» for the opening of the spiral is uncertain due to the position of the edge. On Simbad one finds measurements for the speed from 528 km/s to 560 km/s and for the distance from 8.36 Mpc to 10 Mpc. [145]

«Catalogue of Principal Galaxies (PGC)», Paturel et al. 1989 [144]
DesignationsPGC 9031: NGC 891, UGC 1831, MCG 7-5-46, CGCG 538-52, IRAS 2193+4207, IRAS 2195+4209
Right Ascension (J2000.0)02h 22m 33.0s
Declination (J2000.0)+42° 20' 48"
Morphological TypeS
Dimensions13.1' x 2.8'
Visual Magnitude10.9 mag
Radial Velocity (HRV)528 km/s
Position Angle22°

Finder Chart

The galaxy is located in the constellation Andromeda. Connect the two stars Almach (γ1 Andromedae) and Algol (β Persei). The galaxy is located about 3.5° from Almach on this line. NGC 891 is circumpolar, but is highest in the night sky from July to February.

Chart NGC 891
Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

References

144Catalogue of Principal Galaxies (PGC); Paturel G., Fouque P., Bottinelli L., Gouguenheim L.; Astron. Astrophys. Suppl. Ser. 80, 299 (1989); cdsarc.unistra.fr/viz-bin/cat/VII/119 (2021-02-18)
145SIMBAD astronomical database; simbad.u-strasbg.fr/simbad
149SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
160The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
261Explore - The Night Sky | Hubble’s Caldwell Catalog; nasa.gov/content/goddard/hubble-s-caldwell-catalog (2021-02-08)
313«A New General Catalogue of Nebulae and Clusters of Stars, being the Catalogue of the late Sir John F.W. Herschel, Bart., revised, corrected, and enlarged» Dreyer, J. L. E. (1888); Memoirs of the Royal Astronomical Society. 49: 1–237; Bibcode:1888MmRAS..49....1D
463«Catalogue of one thousand new nebulae and clusters of stars» William Herschel, Philosophical Transactions of the Royal Society of London, 1 January 1786; DOI:10.1098/rstl.1786.0027