Pair of Galaxies NGC 770/2 (Arp 78)

NGC 772
NGC 772: Galaxy in Aries; 500 mm Cassegrain f/7.2; SBIG STL11K; 130-40-40-40 min LRGB; Bernese Highlands; © 2011 Radek Chromik [32]

History

The galaxy NGC 772 was discovered on 29 November 1785 by the German-British astronomer William Herschel with his 18.7 inch reflector telescope. The small companion galaxy NGC 770 remained undiscovered until 3 November 1855. During that night it was discovered by the Irish astronomer RJ Mitchell using Lord Rosse's large 72 inch reflector telescope. [196, 277]

In Halton Arp's 1966 Atlas of Peculiar Galaxies, the two galaxies are listed as Arp 78, a spiral galaxy with a small companion with high surface brightness. [199]

Physical Properties

The two galaxies interact gravitationally with one another and are about 36 Mpc away. [145, 439]

Revised+Historic NGC/IC Version 22/9, © 2022 Dr. Wolfgang Steinicke [277]
Name RA Dec Type bMag vMag B-V SB Dim PA z D(z) MD Dreyer Description Identification, Remarks
NGC 770 01 59 13.5 +18 57 18 Gx (E1) 13.8 12.8 1.0 12.3 1.1 × 0.8 15 0.008199 34.63 32.300 vF, S, R, sp I 112 GC 461=464; UGC 1463; MCG 3-6-10; CGCG 461-16; Arp 78
NGC 772 01 59 19.5 +19 00 27 Gx (Sb) 11.1 10.3 0.8 13.9 7.2 × 4.3 130 0.008246 34.83 30.310 B, cL, R, gbM, r WH I 112; h 181; GC 463; UGC 1466; MCG 3-6-11; CGCG 461-18; KARA 80; Arp 78; IRAS 01565+1845

Finder Chart

The galaxy NGC 772 is located in the constellation Sternbild Aries. The best time to observe is August to February, when it is highest at night.

Finder Chart Pair of Galaxies NGC 770/2 (Arp 78)
Pair of Galaxies NGC 770/2 (Arp 78) in constellation Aries. 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]

Visual Observation

635 mm Aperture: NGC 772 is recognizable as a faint, oval spot. There is no sign of one of its brighter arms. The small neighboring galaxy NGC 770 presents itself as a small, round, diffuse spot. — 25" f/4 Obession Dobsonian, Astrofarm Tivoli, Namibia, 15. 9. 2023, Bernd Nies

Objects Within a Radius of 15°

References