NGC 7332/7339 Galaxy Pair in Pegasus: October 2020 Observer’s Challenge Report #141

Compiled by:

Roger Ivester, North Carolina 

&

Sue French, New York

October 2020

Report #141

NGC 7332/39 Galaxy Pair in Pegasus

Sharing Observations and Bringing Amateur Astronomers Together

Introduction

The purpose of the Observer’s Challenge is to encourage the pursuit of visual observing. It’s open to everyone who’s interested, and if you’re able to contribute notes, and/or drawings, we’ll be happy to include them in our monthly summary. Visual astronomy depends on what’s seen through the eyepiece. Not only does it satisfy an innate curiosity, but it allows the visual observer to discover the beauty and the wonderment of the night sky. Before photography, all observations depended on what astronomers saw in the eyepiece, and how they recorded their observations. This was done through notes and drawings, and that’s the tradition we’re stressing in the Observer’s Challenge. And for folks with an interest in astrophotography, your digital images and notes are just as welcome. The hope is that you’ll read through these reports and become inspired to take more time at the eyepiece, study each object, and look for those subtle details that you might never have noticed before.

Mario Motta: Observer from Massachusetts

I took this friday night Sept 11, and tried for color, got 1 hour Lum, and 45 min each RGB, but.. getting color on small galaxies is rarely very rewarding. Barely a reddish tint is all I see. Taken with ASI6200 camera though the 32-inch scope.

It’s a good thing I took this image last friday! The past few days we have had a dense plume of smoke (Due to the California wildfires) up high at 25,000 feet dimming the sky, below 30 degrees you can very safely stare at the sun. Certainly we are much better off than the poor people out west with the fires, but that smoke and dust is now in the upper atmosphere and covering New England skies.

I estimated a 3 mag loss in the sky last night. Tonight I made visual estimates I normally have a 5.5 mag sky on a good moonless night from my observatory deck.

I will be quantitative now: straight up looking at cygnus, only the brightest stars are seen, Albeiro (mag 3) barely seen, so a loss of 2.5 mags. Don’t forget magnitude is logarithmic so this amounts to filtering of 80% of the starlight out.

At an altitude of 30 degrees up…nearly all stars are gone, Mars and Jupiter appear as a first or second magnitude star, which is a magnitude 4 loss, much dimmer than they should be. This smoke is really thick up there. And just at new moon with “clear” skies, very unfortunate. No more imaging until the skies clear…

Uwe Glahn: Observer from Germany

16-inch, 257x, NELM 6m5+, SQM 21.3, Seeing III “very nice pair; NGC 7332 1:5 spindle with very bright core, extensions to both sides with bright surface brightness and sharp appearance, long SW edge a little better defined, no central dust lane visible; NGC 7339 with totally different characteristics, much lower surface brightness but visible with direct vision, similar elongation with 1:4 but without a dominant core, diffuse extensions, core area clearly mottled but difficult to hold individual structures.


Venu Venugopal: Observer from Massachusetts:

NGC 7332 is an edge-on lenticular galaxy located at about 67 million light-years away, both NGC 7332 and 7339 were discovered by William Herschel in 1784.  NGC 7332 and NGC 7339 form a binary system in the constellation Pegasus and are likely orbiting each other. NGC 7332 is the brighter of the two galaxies. Receding from us at over eight hundred miles per second, they are orbiting each other at about sixty miles per second.

Telescope: 72mm ED f/5 refractor, GEM 45Camera: ZWO 533Exposure time: 57 minutes / 10 second subs / flats/ darksReal time stacked on SharpCapPost Processing software:  Adobe Photoshop

Glenn Chaple: Observer from Massachusetts

  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 (rogerivester@me.com). To find out more about the Observer’s Challenge or access past reports, log on to rogerivester.com/category/observers-challenge-reports.

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