Galaxies NGC 7332 & NGC 7339
![NGC 7332/9](/thumb/0d2c3d994bde0c5922b375936246c26c_fig.webp)
History
The two galaxies were discovered on 19 November 1784 by William Herschel using his 18.7 inch reflecting telescope. He cataloged it as II 233 and II 234 and wrote: «Two. The preceding pretty bright, a little extended in the direction of the meridian. The following faint, extended, nearly in the direction of the parallel of declination, 1.5' long.» [464] His son John cataloged it later as h 2173 (GC 4821) and h 2175 (GC 4824) and first suspected that a third galaxy belongs to that pair. [466] Dreyer cataloged the two galaxies as NGC 7332 and NGC 7339. [277, 313]
Physical Properties
The galaxy NGC 7332 is the brighter of this pair of galaxies, which is moving away from the center of the Local Group at around 1600 km/s. With a Hubble constant of 75 km/s/Mpc, one arrives at a distance of 69 million light-years and a diameter of the galaxy of around 60'000 light-years. With NGC 7332 we are looking directly at the edge, because its axis of rotation is tilted at exactly 90 degrees to our line of sight. [134]
The galaxy NGC 7339 is 43'000 light-years across, smaller than NGC 7332 and about 2 million light-years further away. The axis of rotation of this galaxy is tilted at 85 degrees to our line of sight. [134]
Name | RA | Dec | Type | bMag | vMag | B-V | SB | Dim | PA | z | D(z) | MD | Dreyer Description | Identification, Remarks |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
NGC 7332 | 22 37 24.6 | +23 47 53 | Gx (S0/P) | 12.0 | 11.1 | 0.9 | 12.6 | 4.1 × 1.1 | 155 | 0.003909 | 16.51 | 20.600 | cB, S, mE 156°, smbMN, p of 2 | WH II 233; h 2173; GC 4821; UGC 12115; MCG 4-53-8; CGCG 474-12; KCPG 570A |
NGC 7339 | 22 37 47.0 | +23 47 11 | Gx (SBbc) | 13.1 | 12.2 | 0.9 | 13.0 | 2.8 × 0.7 | 93 | 0.004380 | 18.50 | 22.860 | F, pS, mE 89°, vglbM, f of 2 | WH II 234; h 2175; GC 4824; UGC 12122; MCG 4-53-9; CGCG 474-13; KCPG 570B |
Finder Chart
Both galaxies lie in the constellation Pegasus and are not difficult to find - especially since NGC 7332 is quite bright, but also small. Therefore, you should enlarge the critical search area higher, about 100x should be enough. A small, nearly equilateral triangle about four arc minutes on a side points its southern tip directly at NGC 7332.
![Finder Chart Galaxies NGC 7332 & NGC 7339](/pic/charts/ngc7332_chart.webp)
Visual Observation
200 mm aperture: The NGC 7332 galaxy appears as a small object with a clear north-south elongation in the eyepiece. With a direct view you could see the center and north-south extensions. With averted vision, however, the galaxy appears to double in size. At times one even believes that something like a dust band can be seen, although nothing can be seen on the POSS image.
NGC 7339, the second galaxy in this pair, is proving to be an edge-on. Its longitudinal axis points almost exactly at NGC 7332. In contrast to this, it appears significantly larger, but has a significantly lower surface brightness.