OBSERVER’S CHALLENGE* – OCTOBER, 2020
by Glenn Chaple
NGC 7332/7339 – Galaxies in Pegasus
(NGC 7332, Mag: 11.1, Size: 4.1’ X 1.1’ NGC 7339, Mag: 12.1, Size: 3.2’ X 1.0’)
The deep sky aficionado who has spent time exploring galaxies in the constellation Pegasus is familiar with NGC 7331 and the nearby galaxy group Stephan’s Quintet. For more Pegasus galaxies, look eleven degrees due south for the interesting edge-on galactic pair NGC 7332 and NGC 7339. Both were discovered by William Herschel on September 19, 1784 and entered in his Catalogue of Nebulae and Clusters of Stars as Class II (Faint Nebulae) objects.
Far be it for me to question Sir William’s judgement, but I would humbly opine that NGC 7332 should have been catalogued as a Class I (Bright Nebulae) object. I had no trouble capturing the elongated form of this 11th magnitude edge-on lenticular galaxy with a 4.5-inch reflecting telescope and magnification of 100X. NGC 7339 wasn’t as accommodating. A magnitude fainter than NGC 7332 (and certainly deserving its Class II status), this edge-on spiral required a bigger scope (a 10-inch reflector), ample time to dark-adapt my eyes, and averted vision.
To find these galaxies with GoTo technology, use the coordinates for NGC 7332 (RA 22h 37.4m, dec. +23° 47.9’). If you’re a star-hopper, train your finderscope on the wide pair mu (μ) and lambda (λ) Pegasi (magnitudes 3.5 and 3.9, respectively). After centering lambda in a low-power eyepiece field, nudge your scope 2 degrees westward until a pair of 7th magnitude stars less than a degree apart and oriented N-S enters the field. Center the northernmost of the two in the eyepiece field and switch to a higher magnification. NGC 7332 should immediately be visible. NGC 7339, located 5 arc-minutes east of NGC 7332 will appear as a faint E-W-oriented streak.
NGC 7332 and NGC 7339 appear to form a gravitationally bound system. They lie some 67 million light years from earth.
*The purpose of the Observer’s Challenge is to encourage the pursuit of visual observing. It is open to everyone who is interested. If you’d like to contribute notes, drawings, or photographs, we’ll be happy to include them in our monthly summary. Submit your observing notes, sketches, and/or images to Roger Ivester (firstname.lastname@example.org). To find out more about the Observer’s Challenge or access past reports, log on to rogerivester.com/category/observers-challenge-reports.
Finder Chart for NGC 7332/7339
Taki’s 8.5 Magnitude Star Atlas (takitoshimi.starfree.jp)
Image by Mario Motta (ATMoB), taken with ASI6200 camera though the 32 inch scope.
1 hour Lum, and 45 min each RGB.
NGC 7332/7339, as seen with 10-inch f/5 reflector at 139X. Sketch by Glenn Chaple (ATMoB)