Galaxies NGC 7332 & NGC 7339

NGC 7332/9
NGC 7332/9: Galaxien-Paar in Pegasus; 500 mm Cassegrain 3625 mm f/7.2; SBIG STL11K; 90+35+35+35 min LRGB; Bernese Highlands; © 2011 Radek Chromik [32]

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]

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 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 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 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
Galaxies NGC 7332 & NGC 7339 in constellation Pegasus. 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

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.

Frank H. Leiter

More Objects Nearby (±15°)

References

  • [32] Astrofotografie by Radek, Bernie and Dragan; sternwarte.ch
  • [134] Lyon-Meudon Extragalactic Database (LEDA); leda.univ-lyon1.fr
  • [149] SkySafari 6 Pro, Simulation Curriculum; skysafariastronomy.com
  • [160] The STScI Digitized Sky Survey; archive.stsci.edu/cgi-bin/dss_form
  • [277] «Historische Deep-Sky Kataloge» von Dr. Wolfgang Steinicke; klima-luft.de/steinicke (2021-02-17)
  • [313] «A New General Catalogue of Nebulae and Clusters of Stars, being the Catalogue of the late Sir John F.W. Herschel, Bart., revised, corrected, and enlarged» Dreyer, J. L. E. (1888); Memoirs of the Royal Astronomical Society. 49: 1–237; Bibcode:1888MmRAS..49....1D
  • [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
  • [466] «Observations of nebulæ and clusters of stars, made at Slough, with a twenty-feet reflector, between the years 1825 and 1833» John Frederick William Herschel, Philosophical Transactions of the Royal Society of London, 1 January 1833, Pages: 359-505; DOI:10.1098/rstl.1833.0021