Beyond NGC

[acey]

Last night I was viewing NGC 2692, discovered by W. Herschel in 1790, and in the same high-power field could easily see another galaxy of comparable brightness, missed by Herschel and not in the NGC. He missed it because a foreground star is very close: in fact the impression at the eyepiece was that the star was fuzzy with averted vision. If the star hadn't been there then Herschel would certainly have seen the galaxy, which would probably have appeared brighter than the one he found.

The galaxy he missed is PGC 25130 = UGC 4671. It's marked on Great Atlas Of the Sky by its PGC designation, and marked in Uranometria by its UGC number. Quite a lot of UGCs are pretty easy in a 12", and Uranometria is a good source for choosing targets, but this is one I just happened to come across. The pic below is from the CDS Portal and shows the two galaxies, Herschel's being the one at the bottom. No show-stopper, but visible with a 12" at a dark site.

http://cdsportal.u-s...g.fr/#PGC 25130

[mdstuart]

Very interesting. Thanks for sharing it.

I will see if I can pick them up but I suspect they may be a little too faint for me.

Will need to give the Speculum a good shine first!

Mark

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[Daniel-K]

i ve seen these visually in the 16, a real galaxy photon eating machine. nice to learn a bit of background on the pair

[mdstuart]

Acey

I gave them a go..right overhead at midnight which was a bit of a pain in the dob..

But after a bit of effort I found the two bright stars nearby and could just make out the two mag 14 stars involved with the galaxy pair.

NGC 2692 was only just visible even with averted vision. Very tough for me. I did see it at least three of four times to make sure.

I tried hard for UGC04671 but no luck. I think the fact 2692 was away from those field stars helped. I think I may be able to see the UGC once the field star goes SN or becomes a brown dwarf but until then I am thwarted..

Have you seen 4144 and 4096? They are nice edge on glows I saw recently. Nice and large! Not like 2692!

Mark

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[acey]

Mark, well done on getting NGC 2692 (which is Herschel Class III, "very faint nebulae"), and never mind about UGC 4671, Herschel missed it with his 18" and it was missed by all the subsequent NGC observers. Both galaxies are about mag 13.5 but the UGC is swamped by the nearby star and could easily be missed in a 12". Apparently the galaxy hosted a supernova in 2000 (SN 2000dv) so that might have been a chance to see it with smaller aperture.

I viewed NGC 4096 in 2008 with my 8". Don't have my notes to hand to see what I wrote, but my spreadsheet tells me it's Herschel Class I ("bright nebulae"), which is why I would have aimed the 8" at it. I viewed NGC 4144 in February last year with the 12". It's Herschel Class II ("faint nebulae"). Oddly, 4096 is not in the Herschel 400 list, but 4144 is in the supplementary 400. I gave up on those lists because I found them too idiosyncratic, deciding to stick with Herschel's own historic lists instead.

NGC 2692 is a pretty run-of-the-mill object, and I only mentioned it because of the UGC nearby. I spent most of my session looking at other stuff. Brightest objects of the night were NGC 2639 (H I 204), NGC 2681 (H I 242) and NGC 2693 (H II 823). I'd previously visited NGC 2681 in 2005 with the 8"; it's the brightest of the three, and the only one in the Herschel 400. NGC 2693 is interesting because it has a smaller, fainter companion, NGC 2694, which was easily visible in the 12" at high power but might be very tough in smaller aperture. Herschel saw the main galaxy but missed the companion. The other objects I viewed were all very faint; two were Herschel Class III (NGC 2469, 2505), the rest were missed by him (NGC 2462,2463,2468,2473) and form a group. I failed to see two group members (NGC 2458, 2461), I think because of some misting on the primary. The moon rose at about 11pm so I finished then.

[michael.h.f.wilkinson]

Interesting stuff. There is indeed a great deal to be seen beyond NGC, especially if your scope is up to it.

Oh dear, I can feel a bout of aperture fever coming . I sometimes feel I am beginning to scrape the bottom of the barrel of my 8".