Pair of Galaxies NGC 2798/9

NGC 2798/9
NGC 2798/9: Pair of galaxies in Lynx; 500 mm Cassegrain f/7.2; SBIG STL11K; 260-140-140-140 min LRGB; Bernese Highlands; © 2016 Radek Chromik


On January 14, 1788 the German-British astronomer William Herschel pointed his large 18.7 inch reflective telescope to the sky and saw a faint nebula drifting by, which he cataloged as II 708 and described as «pretty bright, small, stellar». [464] His son John included it in his 1864 «Catalogue of Nebulae and Clusters of Stars» as GC 1788 (NGC 2798 by Dreyer). [467] On March 9, 1874, the British astronomer Ralph Copeland revisited the nebula using Lord Rosse's giant 72 inch reflector at Birr Castle and found another one (NGC 2799) following it. [277]

In Halton Arp's 1966 «Atlas of Peculiar Galaxies», the two galaxies NGC 2798 and NGC 2799 are listed as Arp 283. He noted: «Arc of barely resolved knots curves into nucleus of larger galaxy.» [199]

Physical Properties

NGC 2798/9
NGC 2798/9: Image taken with Hubble Space Telescope. Post processing by Judy Schmidt [165]

This is a pair of interacting galaxies. The gravity of the larger galaxy NGC 2798 pulls stars from the NGC 2799 which fall to the center like a waterfall. Such mergin processes can take place over several hundred million to over a billion years. But due to the sheer amount of space between stars means that stellar collisions are unlikely and stars typically drift past each other. Measured distance is about 28 Mpc [145]

«Revised New General Catalogue and Index Catalogue», «Historically Corrected New General Catalogue», Dr. Wolfgang Steinicke, 2021 [277]
NameRADecTypeBmagVmagDimDreyer DescriptionIdentification
NGC 2798 09 17 22.9+42 00 00Gx (SBa/P) × 0.9pB, S, stellarUGC 4905, MCG 7-19-55, CGCG 209-45, IRAS 09141+4212, KCPG 195A, KUG 0914+422A, VV 50, Arp 283
NGC 2799 09 17 31.0+41 59 38Gx (SBm)14.313.71.90 × 0.5F, cL, vmE, f II 708UGC 4909, MCG 7-19-56, CGCG 209-46, KCPG 195B, Arp 283, VV 50, KUG 0914+422B

Finder Chart

The pair of galaxies NGC 2798/9 is located in constellation Lynx. The best time for observation is November through April, when it is high in the sky during night.

Chart NGC 2798/9
Chart created using SkySafari 6 Pro and STScI Digitized Sky Survey. [149, 160]


145SIMBAD astronomical database;
149SkySafari 6 Pro, Simulation Curriculum;
160The STScI Digitized Sky Survey;
165Flickr: Judy Schmidt; (2021-01-02)
199Atlas Of Peculiar Galaxies, Halton Arp; (2020-12-28)
277«Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; (2021-02-17)
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
467«Catalogue of nebulae and clusters of stars» John Frederick William Herschel, Philosophical Transactions of the Royal Society of London, 1 January 1864; DOI:10.1098/rstl.1864.0001