Pair of Galaxies NGC 3166/3169
History
The two galaxies NGC 3166 and NGC 3169 were discovered by William Herschel on 19 December 1783 using his 18.7 inch reflecting telescope. He classified them as «bright nebulae» and listed them as I 3 (NGC 3166) and I 3 (NGC 3169), both with the notes: «Considerably bright, pretty large, resembling comet, much brighter in the middle.» On 13 December 1784 he also discovered NGC 3156 and listed it as III 255 with the notes: «Very faint, very small, preceding triangle of bright stars.» [463]
While observing NGC 3166 and 3169 (h 684 and h 685) on 30 January 1856 using Lord Rosse's 72-inch reflector, the «Leviathan of Parsonstown», R.J. Mitchell, Lord Rosse's assistant, discovered NGC 3165 and noted: «About 5' south preceding 684 [NGC 3166] is a very very faint ray, extending north and south.» [486]
Physical Properties
| Name | RA | Dec | Type | bMag | vMag | B-V | SB | Dim | PA | z | D(z) | MD | Dreyer Description | Identification, Remarks |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| NGC 3156 | 10 12 41.1 | +03 07 47 | Gx (S0) | 13.1 | 12.3 | 0.8 | 13.0 | 1.9 × 0.9 | 47 | 0.004396 | 18.57 | 22.260 | F, cS, R, psbM, * 9·10 sf 2' | WH III 255; h 680; GC 2028; UGC 5503; MCG 1-26-19; CGCG 36-57 |
| NGC 3165 | 10 13 31.4 | +03 22 30 | Gx (Sdm) | 14.5 | 13.9 | 0.6 | 14.0 | 1.3 × 0.7 | 177 | 0.004470 | 18.88 | vF, mE 0°, 1st of 3 | GC 2037; UGC 5512; MCG 1-26-23; CGCG 36-63 | |
| NGC 3166 | 10 13 45.5 | +03 25 33 | Gx (SB0-a) | 11.3 | 10.4 | 0.9 | 12.9 | 4.8 × 2.3 | 87 | 0.004486 | 18.95 | 22.000 | B, pS, R, psmbM, 2nd of 3 | WH I 3; h 684; GC 2038; UGC 5516; MCG 1-26-24; CGCG 36-64; KCPG 228A; IRAS 10111+0340 |
| NGC 3169 | 10 14 14.7 | +03 28 01 | Gx (Sa) | 11.1 | 10.2 | 0.9 | 12.8 | 4.2 × 2.9 | 45 | 0.004130 | 17.44 | 20.650 | B, pL, vlE, pgmbM, * 11, 78°, 80", 3rd of 3 | WH I 4; h 685; GC 2041; UGC 5525; MCG 1-26-26; CGCG 36-66; KCPG 228B; IRAS 10116+0342 |
Finder Chart
The pair of galaxies NGC 3166/3169 is located in the constellation Sextans. On 19 February it is in opposition to the Sun and crosses the meridian at local midnight. It can best be observed from December to May.
