NGC 70 Galaxy Group

NGC 70
NGC 70: Galaxy group in Andromeda; North is left; 500 mm Cassegrain f/7.2; SBIG STL11K; 120-40-40-4 0 min LRGB; Bernese Highlands; © 2011 Radek Chromik

History

The galaxies NGC 68, NGC 70, NGC 71 and NGC 72 were discovered on September 11, 1784 by the German-British astronomer William Herschel with his 18.7 inch reflector telescope. On October 7, 1855, RJ Mitchell, assistant to William Parsons, 3rd Earl von Rosse, directed the huge 72 inch reflector telescope at this group of galaxies and discovered other galaxies: NGC 67, NGC 69 and NGC 74. The somewhat remote galaxy NGC 76 had to wait until September 22, 1884 to be discovered by the French astronomer Guillaume Bigourdan with a 12.4 inch refractor telescope. His observation also led to IC 1539, a duplicate entry from NGC 70. [277]

Boris Aleksandrovich Vorontsov-Velyaminov lists this group of galaxies in his «Atlas and Catalog of Interacting Galaxies» published in 1959 as VV 166. [432] In Halton Arps' 1966 published «Atlas of Peculiar Galaxies» it is listed under Arp 113 as closely related and interfering spiral galaxies Find. [199]

Physical Properties

NGC 70 belongs to a compact group of seven or eight galaxies and shows similarities to Stephan's Quintet (HCG 92) in the neighboring constellation Pegasus. NGC 68 shows a smaller redshift than the other galaxies in the group and also shows no gravitational changes. It is probably not one of them and is in the foreground. [433, 434] The distance of the group to the Milky Way is around 90 Mpc to 96 Mpc. [145]

«Catalogue of Principal Galaxies (PGC)», Paturel et al. 1989 [144]
NameRA [hms]Dec [dms]mTypeDim [']Btot [mag]HRV [km/s]PA [°]
UGC 16600 17 36.0+30 12 20D1.9 x .915.1483418
NGC 6700 18 14.9+30 03 46E.3 x .215.86844
NGC 6800 18 18.2+30 04 19L M1.2 x 1.114.25803
NGC 6900 18 20.5+30 02 22CB M.3 x .315.86754
NGC 70, IC 153900 18 22.4+30 04 51S M1.6 x 1.414.271690
NGC 7100 18 23.6+30 03 47L M1.5 x 1.214.36716
NGC 7200 18 28.4+30 02 24SBRM1.1 x .914.6724915
NGC 72A00 18 34.3+30 02 09C M.3 x .315.66807
NGC 7400 18 48.7+30 03 39S.8 x .315.5
NGC 7600 19 37.7+29 56 07C1.0 x .914.0738980

Finder Chart

The NGC 70 galaxy group is located in the constellation Andromeda. The best observation time is July to September, when it is highest at night.

Andromeda: NGC 70
Chart NGC 70
Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]

Visual Observation

320 mm Aperture: Of the galaxy group around NGC 70, which counts 8 to 10 galaxies, only the four bright ones were easy to identify with the 12.5" Dobsonian. They were NGC 68, NGC 70, NGC 71 and NGC 72. The other much fainter galaxies are then challenges for a larger Dobsonian. — 12.5" f/4.5 Ninja-Dobsonian, Glaubenberg, 2. 8. 2022, Eduard von Bergen

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
199Atlas Of Peculiar Galaxies, Halton Arp; ned.ipac.caltech.edu/level5/Arp/Arp_contents.html (2020-12-28)
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)
432«The Atlas and Catalogue of Interacting Galaxies» B.A. Vorontsov-Velyaminov (Moscow 1959); ned.ipac.caltech.edu/level5/VV_Cat/frames.html (2021-09-25)
433«Tidal effects as criteria for membership in small groups of galaxies: application to VV 166.» Kormendy, J.; Sargent, W. L. W.; Astrophysical Journal, Vol. 193, p. 19-25 (1974); DOI:10.1086/153122
434«Galaxy collisions in dense groups.» Hickson, P.; Richstone, D. O.; Turner, E. L.; Astrophysical Journal, Vol. 213, p. 323-326 (1977); DOI:10.1086/155158