Galaxies NGC 147, NGC 185

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 [32]
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 [32]

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]

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, © 2022 Dr. Wolfgang Steinicke [277]
Name RA Dec Type bMag vMag B-V SB Dim PA z MD Dreyer Description Identification, Remarks
NGC 147 00 33 11.7 +48 30 26 Gx (E5/P) 10.5 9.5 1.0 14.5 13.2 × 7.8 25 -0.000644 0.730 vF, vL, iR, gsmbM * 11 h 29; GC 72; UGC 326; MCG 8-2-5; DDO 3; CGCG 550-6
NGC 185 00 38 57.6 +48 20 14 Gx (E3) 10.1 9.2 0.9 14.4 8 × 7 35 -0.000674 0.670 pB, vL, iR, vgmbM, r WH II 707; h 35; GC 90; UGC 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 to January, when this circumpolar constellation is highest in the sky.

Finder Chart Galaxies NGC 147, NGC 185
Galaxies NGC 147, NGC 185 in constellation Cassiopeia. Charts created using SkySafari 6 Pro and STScI Digitized Sky Survey. Limiting magnitudes: Constellation chart ~6.5 mag, DSS2 close-ups ~20 mag. [149, 160]

Objects Within a Radius of 15°

References

  • [32] Astrofotografie by Radek, Bernie and Dragan; sternwarte.ch
  • [145] SIMBAD astronomical database; simbad.u-strasbg.fr/simbad
  • [149] SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
  • [160] The 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