Pair of Galaxies NGC 770/2 (Arp 78)
![NGC 772](/thumb/31b1b7a7d948148645e0f66b464ee3a7_fig.webp)
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]
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)](/pic/charts/ngc772_chart.webp)
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