NGC 691 Galaxy Group

NGC 691
NGC 691: Galaxy group in Aries; 500 mm Cassegrain f/7.2; SBIG STL11K; 90-30-30-30 min LRGB; Bernese Highlands; © 2011 Radek Chromik

History

The galaxies NGC 678, NGC 680 and NGC 697 were discovered on September 15, 1784 by the German-British astronomer William Herschel with his 18.7 inch reflecting telescope. He did not come across NGC 691 until November 13, 1786. The discovery of NGC 694 by the German astronomer Heinrich d'Arrest did not take place until December 2, 1861. He used an 11 inch refractor telescope. IC 167 was discovered on January 4, 1889 by the French astronomer Guillaume Bigourdan with a 12.4 inch refractor. The tail light of this discovery round is IC 1730 which was discovered on January 17, 1896 by the French astronomer Stephane Javelle with the 76 cm refractor telescope of the Observatoire de Nice. [196, 277]

Physical Properties

These galaxies belong to the NGC 691 galaxy group, which is located approximately at a distance of 27.8 Mpc to 40.9 Mpc from us. Some sources also include NGC 695 in this group, but their distance is about 135 Mpc, which means it is far in the background. [145]

«Catalogue of Principal Galaxies (PGC)», Paturel et al. 1989 [144]
NameRA [hms]Dec [dms]mTypeDim [']Btot [mag]HRV [km/s]PA [°]
NGC 67801 49 25.2+21 59 51SB4.1 x .813.3283678
NGC 68001 49 47.3+21 58 14E1.8 x 1.612.92808
IC 173001 49 58.0+21 57 52L M.8 x .515.3
NGC 69101 50 41.7+21 45 35S R3.4 x 2.512.3266595
NGC 69401 50 58.1+21 59 50C.6 x .414.32949160
IC 16701 51 08.3+21 54 50SB2.7 x 1.813.6293595
NGC 69701 51 17.2+22 21 32SB4.4 x 1.412.83117105

Finder Chart

The NGC 691 galaxy group can be found in the constellation Aries. The best time to observe is August to February, when it is highest at night.

Chart NGC 691
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
196Celestial Atlas by Curtney Seligman; cseligman.com/text/atlas.htm (2020-12-28)
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)