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View Full Version : Object of the Week - November 13th, 2016; NGC 691 Group



Paul Alsing
November 16th, 2016, 05:20 AM
Object of the Week - November 13th, 2016; NGC 691 Group, including NGC 678, NGC 680, NGC 697, NGC 694, IC 167, IC 1730

R.A. (NGC 691) R.A.: 01h50m41.7s Dec.: +21°45'36" (Aries)
Size: (NGC 691) 2.9'x 2.0'
Mag: (NGC 691) 12.30 B

I had the pleasure of sharing a mid-week observing session with old friends in the local Anza Borrego desert in Southern California over 2 nights, November 2 & 3. On night #2, it was late, I was a little tired and feeling a little lazy, so I put the Argo Navis in 'tour' mode, in Aries, and just mindlessly started hopping from one galaxy to the next, having a great time, sharing the views with the others (Debbie Searle, Kemer Thomson and John Hoey). After a while I came across NGC 691... and the adventure began!

NGC 691 is a nice bright, round, face-on spiral (Sbc), available to telescopes of almost any size... and he has friends! Several friends! This picture has north up...

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Set in a very nice star field, and using my Ethos 13 (.4° FOV), which spends about 80% of the time in either my telescope or in Debbie's, I immediately saw 2 or 3 other galaxies nearby. 18' northeast is NGC 680 (mag 12.9), an almost round elliptical galaxy, and about 5' ENE of 680 is NGC 678 (SBb. mag13.30 B), an edge-on spiral. Spending a little more time looking around this FOV we found (2) more galaxies, IC 1730, (mag 15.60 B) a faint lenticular, less than an arc-minute across, residing about 4' NW of NGC 680, and IC 167 (SC, mag 13.60 B), which is about 11' NW of NGC 691. IC 167 has 2 arms, barely detectable, but nonetheless observed. This picture, labeled, has north to the right...

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There is an elongated, lazy loop of stars running from NGC 691 towards the NGC 678/680 pair and it contributes nicely to the overall beauty of this FOV, as does another sprinkling of stars on the northern edge of the FOV.

As we all do (well, I do), I started slewing around looking for more neighbors, and just north of this NGC 691 group NGC 697 popped into view (SABc, mag 12.80 B), a spiral that is clearly in between edge-on and face-on, another bright beacon... along with a very nice, bright double star, 1 Ari (ADS 1457A, STF 174A, 5.87+7.2 mag, Sep 2.90"). I really like double stars near galaxies. Doesn't everyone?

None of these guys is particularly spectacular on its own, but as a group they are just terrific. I think I will take another look at them when I observe during the next new moon.

As always, give it a go and let us know

Steve Gottlieb
November 17th, 2016, 04:22 PM
The NGC 691 group (also called the NGC 697 group) is in my large notebook of finder charts of favorites galaxy groups!

I thought I'd mention that there's a fairly bright (mag 9-10?) uncatalogued double star right off the northeast edge of NGC 691. The separation is roughly 7", but it was missed by the Struves, etc.

Also, IC 167 caught the attention of Halton Arp -- it's Arp 31 and placed in his category of spirals with "integral sign" shapes. I'm guessing its two stretched spiral arms resulted from a past encounter with one of its neighbors in the group.

My notes on these galaxies is here (http://www.astronomy-mall.com/Adventures.In.Deep.Space/NGC%200001-999.html). Scroll down aways :D

KidOrion
November 18th, 2016, 03:17 PM
I love this group. I first read about it in a Ken Hewitt-White S & T column from several years ago ("Checking Off the Galaxies at 1 Arietis"), and I give it a look almost every time I'm out in the fall--it's easy to find without a chart, and it's got a lot of variety.

Great choice!