Galaxies NGC 147, NGC 185

History

On 30 November 1787 William Herschel discovered a nebula which he cataloged as II 707 (class II = faint nebulae) and described as follows: «pretty bright, very large, irregular round, very gradually much brighter in the middle, resolvable, 5 or 6 diameter» [464] On 8 September 1829 his son John discovered another nebula which he cataloged as h 29. He noted: «very faint, very large, irregular round, 4..5' diameter, loses itself insensibly, has a star 11 mag in centre.» [466] Willian Herschels discovery was added by J. L. E. Dreyer as NGC 185 and the one of his son as NGC 147. [313]

NGC 147
NGC 147: Galaxy in Cassiopeia; 500 mm Cassegrain f=3625 mm f/7.2; SBIG STL11K; 210-60-60-60 min LRGB; Bernese Highlands; © 2020 Radek Chromik
NGC 185
NGC 185: Galaxy in Cassiopeia; 500 mm Cassegrain f=3625 mm f/7.2; SBIG STL11K; 220-60-60-60 min LRGB; Bernese Highlands; © 2015 Radek Chromik

Physical Properties

Both galaxies are elliptical dwarf galaxies and companians of the Andromeda Galaxy (M 31), which is roughly 7° (≈ 90 kpc) away. The brighter one is NGC 185, which shows very active star formation and dust near its center. NGC 147 and NGC 185 are gravitationally bound to each other. Distance of NGC 147 ranges from 708 to 730 kpc. NGC 185 is slightly closer with distances ranging from 630 kpc to 700 kpc. The angular separation between NGC 147 and NGC 185 is about 58 arc minutes, which gives a true distance of 12 kpc. [145]

Revised+Historic NGC/IC, Version 22/9, © Dr. Wolfgang Steinicke [277]
NameRADecTypebMagvMagDimDreyer DescriptionIdentification, Remarks
NGC 14700 33 11.7+48 30 26Gx (E5/P)10.59.513.2 × 7.8vF, vL, iR, gsmbM * 11UGC 326, MCG 8-2-5, DDO 3, CGCG 550-6
NGC 18500 38 57.6+48 20 14Gx (E3)10.19.28 × 7pB, vL, iR, vgmbM, rUGC 396, MCG 8-2-10, CGCG 550-9, IRAS 00362+4803

Finder Chart

The galaxies NGC 147 and NGC 185 are located in the outskirts of the constellation Cassiopeia. Best observing time is in the months July through January, when this circumpolar constellation is highest in the sky.

Chart Galaxies NGC 147, NGC 185
Galaxies NGC 147, NGC 185 in constellation Cassiopeia. Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

More Objects Nearby (±15°)

References

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
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)
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
464«Catalogue of a second thousand of new nebulae and clusters of stars; with a few introductory remarks on the construction of the heavens» William Herschel, Philosophical Transactions of the Royal Society of London, 1 January 1789; DOI:10.1098/rstl.1789.0021
466«Observations of nebulæ and clusters of stars, made at Slough, with a twenty-feet reflector, between the years 1825 and 1833» John Frederick William Herschel, Philosophical Transactions of the Royal Society of London, 1 January 1833, Pages: 359-505; DOI:10.1098/rstl.1833.0021