Object Of The Week, November 15, 2015 - NGC 7137

Object Of The Week, November 15, 2015 - NGC 7137

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NGC 7137, UGC 11815, MCG +04-51-005, PGC 67379

Pegasus

RA
21 48 13
DEC
+22 09 34

Type Spiral Galaxy

Size 1'.6 x 1'.4

NGC 7137 was found on November 17, 1784, by Friedrich Wilhelm Herschel, commonly known as William Herschel, using his famous 20 foot reflector (18.7" aperture). He cataloged the object as #261in class II, Faint nebulae, as part of his April 27, 1786 paper "Catalogue of One Thousand new Nebulae and Clusters of Stars" (pp. 457-499 [ADS: 1786RSPT...76..457H]). His description read "Faint, irregularly Round, less than 1' diameter". I haven't been able to determine the observing conditions of that particular night, but maybe someone who has studied Herschel's papers in more detail can enlighten us.

NGC 7137 lies at a distance of about 25 Mpc, placing it at the western edge of the Perseus supercluster. Based on 2MASS data it is determined to be about 28 x 24 kpc in size.

Attachment 1874

NGC 7137 lies in the western most part of Pegasus, very close to the Milky Way. There are no other NGC objects in a ten degree radius around it. Only 13 log entries exist in www.deepskylog.org so I guess it is not a very popular object. Nevertheless I found it a very impressive sight in my 20" telescope!

After finally having completed the H400 list I started observing objects from the HII and Herschel 2500 lists. I observed the galaxy on October 8, 2015. My notes are

At 545x I see a large, round smudge next to a fairly bright star. Occasionally a stellar nucleus lights up in the center. I see two arms: one on the west side towards the star and one on the south side running west. The third arm to the north east remains invisible. On the south side I see a dark lane separating the arm from the nucleus and another one on the west side. Despite it being a faint object it is very spectacular!

I made this very crude drawing on my iPhone. Yes, I know there's a lot to improve but it is the thought that counts :-)

Attachment 1875

As always,

"Give it a go and let us know!
Good luck and great viewing!"

Logged two observations for this galaxy, both using my 12" SCT (179x / 27'). One in 2011 under average Dutch skies and one in 2013 under steady dark skies in France.

30 September 2011​
A round patch, even in brightness, no detail visible, no difference when using AV. 1/4 FoV to the SE are two mag. 10.5 stars aligned WNW-ESE, 1/4 FoV to the NW is a mag. 10 star. Rated it 3/10.

5 September 2013
A round, quite bright glow, very faintly shows irregular structure, even in brightness when not using AV. On the WNW edge is a mag. 14.5 star. Rated it 4/10.

I suspect scopes >12" aperture are needed to reveal true detail. A nice galaxy and a nice OOTW nonetheless!

Very nice object and great debut Wouter.

I've only one logged observation and sketch with my 27". Your sketch shows much the same detail as with the 27". Not bad for 20" + iPhone, more please.

27", 419x-586x, NELM 6m5+
Attachment 1876

Impressive observations here. At least in my "survey mode", I did not notice any detail in 16". The noted sharpness of the edges was probably a sign of the arms, but that doesn't count.

"NGC 7137 [II.261, not in Herschel 400] is a modest (44 kly) spiral in NW Pegasus 85 Mly away. It is located near the faint neaked-eye 12 Peg E of the Swan’s E wingtip. A faint star is seen on the W edge at 225x. The galaxy is visible already with 40 mm Pentax, but remains featureless and essentially round at the higher mag. The edges are a little sharp."

Thanks for the positive responses everyone. I'll be back with more :)

Uwe, it looks from your sketch that you indeed saw similar details as I did, but clearer. I may have spotted two arms and you clearly saw all three of them. Still, I am very happy with my observation :)


Clear skies, Wouter

My notes from 2012 with my trusty 10 inch stated NGC 7137 was only just visible with averted vision. I observed it in a 8mm Hyperion lens.

I picked up a faint mag 14.7 field star to the N of the galaxy.

Must go back with the 16 inch!

Mark

When Herschel began the sweep (#319) on 17 Nov 1784, the moon was well up ("the moon pretty bright"). He swept up NGC 7137 about 9 minutes later, so the view was certainly compromised to some extent by the moon (it set more than 2 hours later).

That brings up an interesting thought - every so often we've all come across an object that Herschel discovered and wondered why he didn't see a nearby but somewhat fainter object. Perhaps it was because the Moon was brightening the sky!

Perhaps it was because of the nature of the way that Herschel swept that could also cause this. Wolfgang gave a very interesting presentation on this to the Webb Soc annual meeting a few years ago on this and hopes to get a book out about it if he can find a publisher.

Owen

Thanks for the additional info, Steve!