Stephan's Quintet and other 12-inch targets

[acey]

No moon, and a forecast of clear skies – not a thing to be missed. I headed out into the mag-6 wilds with the 12-inch flextube, intent on tracking down some galaxies in Pegasus.

To start, though, I ticked off some DSOs in Aquila, prompted by my Herschel project. Of the six open clusters I logged, the most appealing were the pair NGC 6840/43, (the others were 6837, 6755, 6756, 6858). Also two globs – 6749 (faint and tough) and 6760 (rather large, very easy, and with a hint resolved stars). And two planetaries – 6804 appeared slightly fan-shaped with 2 or 3 involved stars (one of these is the central star, though I couldn’t hold it with direct vision), and 6772 (very tough). The UHC spoiled the view of 6804 by filtering out the stars, but I wouldn’t have found 6772 without it. I also tried for 6803, a planetary so small, apparently, it looks almost stellar. Try as I might, I couldn’t unpick anything from the field stars, with or without the UHC, and eventually gave up. Still, ten objects in under 2 hours was a nice start.

Recharged with caffeine and fuelled with half a bar of chocolate (Galaxy of course) I headed for Pegasus, making NGC 7331 my launch point. This object features on anyone’s “best non-Messier” list and I’d viewed it several times previously with an 8-inch. Seeing it for the first time with the bigger scope, I certainly saw more detail though wouldn’t call it a “wow” by comparison with my earlier views. The western side of the core showed a definite sharp edge indicative of a dark lane, and a glance was enough to show one of the galaxy’s companions – I’d come back to that.

But 7331 is the gateway to Stephan’s Quintet, and that’s where I went next. Again, this is an object I’d viewed with the 8-inch, and my first impression with the 12-inch wasn’t overwhelming. The five galaxies are small, closely grouped, rather faint, and need time - in fact I spent about an hour on them. It was worth it.

7320 is the brightest and easiest of the five, next to pop into view is 7318; and it only took a moment for me to see the two-lobed appearance of the latter, because it is actually 2 galaxies (7318A and 7318B). After spending long enough, I was able to see dark space quite clearly between the pair. The fourth member, 7317, was not too hard either, though a superimposed star helps camouflage it initially. The real toughie, I found, was 7319. In photographs it’s a prominent spiral with a long arm extending outwards a considerable distance, but I could only glimpse it with averted vision.

Looking back at my 8-inch observation, I reckon I saw 7320 and -17, plus -18AB as single (which is how NGC originally listed it anyway). With 12-inches I definitely saw all five, eventually – and felt very pleased about it – but it was harder than I expected.

Going back to 7331, I easily saw its nearby companions 7336, -35, -40 and -37; all small and without obvious cores but distinctly visible, with 7335 brightest.

Next I tried the Pegasus I cluster. The close pair NGC 7626 and 7619 form the easily-found core (I’ve observed those two with the 8-inch). The other galaxies in the vicinity are smaller and fainter – but I managed 7611, -23 , -17, -31 without much difficulty.

Two things interrupted my observations – some high cloud, and the snapping of my pencil! Cue a bit of ruminative sharpening.

I decided to try and add another entry to my Abell galaxy cluster project, so went for Abell 2666 in Pegasus. This was tough, and I realised that it was a mistake in this instance to rely on Uranometria, since the main galaxies are so tightly packed. I would have been better to print a more detailed chart or take an image for reference – I should do that in future. As it was, I found something fairly easily which I took to be NGC 7768 (the brightest cluster member), but nothing else was popping out at me, and I had no way of knowing exactly where in the field of my 11mm Plossl I ought to be looking. In fact I should have been looking right around 7768, and will know next time.

By now it was gone 4a.m., and really time I gave up, but the sky was looking fully clear again and there was still at least half an hour of full darkness to go…

So I headed south of the Abell cluster to the galaxy triplet NGC 7769/70/71, and this turned out to be a nice easy way to finish. 7769 was round and prominent, while just to the east lay an elongated patch that I could soon split into two distinct galaxies, 7770 being like a little chip cut off the flank of larger 7771.

Then it really was time to quit. Why can’t there be more nights like that?

Andrew

[albedo0.39]

Hi there Acey - I think your observing report is seriously impressive and to stay up until 4.00 is top drawer effort. Quite how you managed to spend an hour on SQ is altogether something else... I admit, I do not have this kind of patience so I`m a little in awe....

I think the Mag 6 was the deciding factor though so well done.. .where did you observe from ?

[Talyn]

The real toughie, I found, was 7319. In photographs it’s a prominent spiral with a long arm extending outwards a considerable distance, but I could only glimpse it with averted vision.

I was also looking at Stephan's Quintet last night. NGC 7319 really is a swine of a thing; I saw it eventually, but only after a LOT of averted vision staring. Because it wasn't very transparent here last night, SQ kept disappearing and reappearing, which did not make life easy.

I also tried the Pegasus 1 cluster, but didn't see it, so I am going to have another crack at that one tonight.

Great report. Which version of Uranometria are you using? The newest one or the edition (one red volume, one blue volume) before?

[mike.brightmore]

That was one impressive nights observing. Long clear nights like that just don't come round often enough. A really good report that I feel like reading again.

[Andrew]

Excellent report - sounds like a great night with loads of interesting objects. I have never tried to look for Stephan's Quintet, but I will give it a go soon.

[Doc]

Mag 6 skies must be fantastic and thats the difference seeing SQ and not. I have no chance in my 4.5 skies.

Lots of great objects captured there well done.

[mdstuart]

Lovely report, you have an extra 2 inches on me and darker skies. I just loved the HEADLIGHT GALAXIES NGC 7619 and NGC 7626 I could make out 7611 and 7623 just...

NGC 7769/70/71 are not on my to do list but given your observation I will check them out in my database to see what the sbr is and whether I have a chance to pick them up.

I did like that faint globular 6760 when I saw it back in July..

I also did the planetaries 6803 and 4. 6803 was easier for me to detect by switching the OIII in and out. 6804 was much fainter but better in the OIII but also very small. Perhaps my 6.4mm in the 1200mm dob is not high enough power for this type of object? You do not mention 6781 which to my eyes was much larger and fine in the OIII..?

Lovely review anyway, hope you have many more good nights..

Mark

[SAB]

Excellent report! Very much enjoyed it as PNe's and galaxies are my fave objects.

I also observed NGC 6803 and 6804 with my 12" a couple of nights ago. NGC 6803 is extremely tiny, only 5 arc seconds in diameter (some sources quote as little as 3") so you'll have to use as much power as possible. It is bright at 11th mag though, so tends to look exactly like the field stars! To me it appeared stellar all the way up to 283x, only at 326x I could see a tiny, and i mean TINY disk. You need to blink with an OIII at moderate to high powers to detect it, the stars around it will dim exposing the nebula.

I also did the planetaries 6803 and 4. 6803 was easier for me to detect by switching the OIII in and out. 6804 was much fainter but better in the OIII but also very small. Perhaps my 6.4mm in the 1200mm dob is not high enough power for this type of object? You do not mention 6781 which to my eyes was much larger and fine in the OIII..?

Lovely review anyway, hope you have many more good nights..

Mark

That'll yield only 187x, which is nowhere near high enough for NGC 6803. You'll need atleast 280-300x to discern the disk, perhaps even more.

[acey]

Thanks for all the comments and feedback - very helpful.

My highest power is 250, using a 6mm TMB planetary that I just got and was using for the first time - very nice, I found, for deep-sky. But evidently not enough for the elusive 6803. Maybe I need to check out if there's a 5mm version...

I realised from the Luginbuhl and Skiff description that 6803 was going to be tough and maybe not worth spending too much time on - but I ought to have another go next time I'm in that neck of the woods (er, sky). I was actually after just 4 Aquila objects to tick off my Herschel list, the others happened to be in the vicinity.

I observed the planetary NGC6781 a few years ago with the 8-inch, I just had a look back at my notes and I did indeed find it large and conspicuous though also "pale and ghostly".

I use the latest edition of Uranometria (two blue volumes). My Herschel list had two of the Aquila objects (6840/43) described as "not plotted on Uranometria" but they were plotted on mine so it must have referred to the earlier edition.

I observe from rural Northumbria, a bit of a drive, and not something I can do too often, so when I do it I make it worth my while and put in as many hours as I can. Skies are dark though there's still more near-horizon light-pollution than I'd like. Still, the Milky Way looked absolutely lovely.

[themos]

Hello there, did you find any dark skies in Crete?

[acey]

Hi Themos - I was in the wrong place at the wrong time: moon, mountains to the south, and too much light pollution from the resort. But I visited a friend's where the situation was a lot better - and got a great view of some Perseids!