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Galaxies: Hickson Compact Groups - some seriously faint fuzzies


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Hello all, a challenging end to the 2020-21 observing season here at c.57N.

A delayed report here due to work and family - this was on the night of April 11th into the wee hours of the 12th. Apologies for my brief descriptions of each HCG below. 

This was my last shot to take the 20" dob out to dark skies in the Cairngorms before astro darkness was lost for the summer. I haven't had a decent night with the scope in quite some time.

Bitterly cold (by UK standards) in the region of -6 to -8C in the remote Scottish glen that night, but very clear out despite the so-so forecast. Good thing, considering how much work it took to get there. Still, it was a lot colder than I anticipated.

Setup to observing took about 30 minutes or less. GOTO alignment quite good. Extra 1.5kg on top of the supplied counterweights.

SQM-L readings consistent throughout the night between 21.68 and 21.70, so quite good, certainly no complaints there, though I've had readings of 21.85 from this spot. Once eyes dark adapted, Auriga was initially lost in a sea of stars, equally hard to make out Leo at first, then everything fell into place. Amazing.

My goal - Hickson Compact Groups of galaxies, as many as my greedy eyes could find!

Got seven HCGs - not a bad result I suppose, some were surprisingly good, others were incredibly faint on the very limit of detection (to my eyes anyway) and not a great deal to say other than the faintest of elongated smudges with averted vision, but still a great night. Been wanting to see some of these for several years now. 

HGCs 44 (Leo Quartet), 51, 57 (Copeland's Septet) 59, 61, 79 (Seyfert's Sextet) and HCG 92 Stephen's Quintet (just, and I mean just barely)

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Eyepieces: 13mm APM to locate (153x), then 9mm APM (222x) to move in or 10mm BCO (200x) for the really challenging ones. I didn't get on very well with it when I first bought it, but the 10mm BCO is proving to be the top dog in my eyepiece case for the most challenging galaxies and PN, though with the 10mm BCO's miniscule FOV, it's a lot easier to locate tiny objects first using the 13mm or even 20mm APM, then dive in with the BCO.

The suspects:

HGC 44 aka 'Leo Quartet' - I've seen this cluster before,  but it was coming through loud and clear. By far the brightest of the bunch. 

HGC 51 - 6 galaxies in this one, but no way I could resolve them. The view was an extremely faint, almost circular glow coming through the eyepiece. Still, a hit.

HCG 57 - Copeland's Septet (6 galaxies) Seemed quite similar to 51, almost a circular ring of a.) slightly brighter sky, or b.) extremely faint fuzzies, take your pick! Wish I could have resolved more here. *Update - Reiner Vogel is saying 57 is essentially a lot easier to see than Seyfert's Septet, so there is a reasonable chance I missed 57 altogether and picked up some obscure galaxy in the neighborhood... Must revisit!!

HCG 59 - Probably the faintest of the lot, after some time poking around the area, I could make out two extremely faint fuzzies, but that was it. 

HCG 61 - aka 'The Box' Now we're talking! After seeing some of the others, this one make me shout out loud at the eyepiece. Four beautiful galaxies seemingly set at right angles to one another, all shining brightly. Good stuff. Highly recommend!

HCG 79 - Seyfert's Sextet - this one in photos looks amazing and one of the galaxies has a 'tidal tail'. I could resolve two of the galaxies (one might have been two superimposed galaxies) and the faintest of 'swishes' which may have been another galaxy, most likely PGC 56578, a mag 15.17 - 15.36 SBc galaxy.  I'd need either a bigger scope, EEVA on the 20" or something like a 20" binoscope to confirm that. In other words, silly money I unfortunately don't have! :) 

HCG 92 - Reached its highest point in the sky c.3am. The famous Stephan's Quintet. I'd love to say it was an explosion of fireworks with an choir of angels in the background, but it was fairly low on the horizon 23-26deg max, and it was simply the faintest of smudges... another one to revisit based on Reiner Vogel's comments, the galaxies in here are pretty bright with some at mag13/14 so again, I may have been off the mark with whatever I saw and goto may have put me off just enough to make it a goose chase... next time!

Definitely want to revisit all of these again someday and tease a bit more from them, but quite happy with the results here. 

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Meant to add, about halfway through the night, just to compare, I swung over to M101 and M51 with the 9mm APM at 222x to see if my eyes and scope collimation etc were up to speed.

M101 - stunning, with clear spiral arms gradually fading away from the core. *WOW*

M51/51a - TREBLE WOW. Near astro-photo quality. In greyscale of course! I could have spent ages staring at this.

So yes, things seemed to be optimal.

A very good, challenging evening to say the least. I hope to revisit some HCGs again as soon as possible. As crazy as it sounds, the 20" felt like the minimum to even begin to tease out detail, but maybe it's just my eyes. I could easily imagine a 28"- 36" dob under pristine desert skies being more in-line with easy, direct observing of some of these. EEVA on the 20" would also be a more realistic option, hmmm....

One final note - I recently bought a super cheap £28 pair of small 'Kylietech' 12x42s to throw in the van for work, etc. I wasn't expecting much to say the least, but they are surprisingly good! I was able to make out M51 as a faint, tiny object with them lying on my back, couldn't believe it. That's dark skies for you. I think rebadged versions of these are sold by Celestron etc in the £90 range. 

Anyway...M51 with a cheap pair of tiny binoculars, good stuff...

Cheers all! 👍

Night with some HCGs.jpg

Edited by Ships and Stars
Add Reiner Vogel reference
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9 minutes ago, Stu said:

Sounds like an amazing night! Great report, thanks!

Thanks Stu, it was a long time coming! Feels like ages ago already. I can't afford a bigger scope, nor could I transport it, so I think from here, EEVA on the 20" is the next leap forward. I would love to have made out substantially more detail on these, but also quite happy to have detected some of them in the first place.

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I bet you’re glad you went straight in at the deep end all those months/coupleofyears ago and arrived home with a 20”. We certainly are! I’m in the market for a similar sized dob and you are providing lots of inspiration not to mention obs lists!

Thanks

Magnus

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1 minute ago, Captain Magenta said:

I bet you’re glad you went straight in at the deep end all those months/coupleofyears ago and arrived home with a 20”. We certainly are! I’m in the market for a similar sized dob and you are providing lots of inspiration not to mention obs lists!

Thanks

Magnus

No regrets at all! Just luck I ended up with it. When I was looking for my first scope, work was really busy and an unused 500p came up at a good price. I thought a.)  I may never be able to lift this when I get older, b.) my eyes won't get any better, and c.) I may end up living in an urban area again. That settled it!

I haven't regretted the purchase a a single moment. The 500p seems to get poor reviews for mirror quality, but I've seen so many challenging faint objects, and so many amazing, detailed views of brighter objects that I've no real complaints at all. Little things like the mirror cover and goto drive cable attachments could be improved, but it's all tolerably small details.

I hear they've redesigned the 500p primary with fused mirror supports or something to that effect, but I think I got lucky with mine. Besides, at f4, collimation is pretty critical, especially at higher mag I suppose, but it holds collimation very well. 

Now I'm hoping EEVA comes down a bit in price, it would even work really well with my 300p flextube.  

I'd say go for the big scope, take good care of it and enjoy. You will get to see things only a relatively small number of people have seen before and if the day comes that you need to sell it, the resale value will remain, especially if bought second hand. 

Cheers !

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40 minutes ago, Captain Magenta said:

We certainly are! I’m in the market for a similar sized dob and you are providing lots of inspiration not to mention obs lists!

A big dob is highly recommended for deep sky exploring- eagerly waiting to see what you get Magnus!

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29 minutes ago, Ships and Stars said:

The 500p seems to get poor reviews for mirror quality

There are many that do the "armchair" mirror analysis using many references of test, zygos, star test and who knows what. The fact is that your scope is showing you so much more than any " high spec" smaller mirror could. I support my statement by de collimating  my 24" a good bit and then putting it up against my 15" very well collimated- and yes the 24" still shows more of everything DSO wise. 

Excellent report Robert and keep up the good work!

ps- Stephans Quintet likes good seeing, not just transparency. Under these conditions I use 357x on it with a very good copy of a 7mm KK ortho. This really opens the object up. My 8mm Delos does vg as well.

Edited by jetstream
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11 minutes ago, jetstream said:

There are many that do the "armchair" mirror analysis using many references of test, zygos, star test and who knows what. The fact is that your scope is showing you so much more than any " high spec" smaller mirror could. I support my statement by de collimating  my 24" a good bit and then putting it up against my 15" very well collimated- and yes the 24" still shows more of everything DSO wise. 

Excellent report Robert and keep up the good work!

ps- Stephans Quintet likes good seeing, not just transparency. Under these conditions I use 357x on it with a very good copy of a 7mm KK ortho. This really opens the object up. My 8mm Delos does vg as well.

Thanks Gerry! Good to hear from you. Sorry I've been off the forum quite a lot lately, working away and family keeping me busy at home.

Interesting experiment between the 24 and the 15. Sounds right!

I wish I'd have read Vogel's observations just before I left that night. There is a good chance I flat out missed a couple of these and landed on some other faint galaxy close by. Stephan's Quintet in particular should have been more obvious in my mind, albeit still faint. That's ok, I will definitely return to these objects next time. 

The box was really good, that's one many people should be able to observe under decent skies. 

I can't believe Vogel has seen all 100 HCGs, that's dedication! I'm definitely printing out his observing reports or picking up a copy if he has a guide published.

Wished I'd had it with me, but in a rush as always :)

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Great report - I really enjoyed reading that :thumbright:

Despite having "back yard" skies and a max aperture of 12 inches to use I love to press deep into the sky as far as my conditions / scope will allow.

I have managed to see the 4 members of the Leo Quartet and one or two of the brightest members of some of the other groups you mention. It is a thrill when you pick up one of these very faint and distant smudges of light :icon_biggrin:

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6 hours ago, John said:

Great report - I really enjoyed reading that :thumbright:

Despite having "back yard" skies and a max aperture of 12 inches to use I love to press deep into the sky as far as my conditions / scope will allow.

I have managed to see the 4 members of the Leo Quartet and one or two of the brightest members of some of the other groups you mention. It is a thrill when you pick up one of these very faint and distant smudges of light :icon_biggrin:

Indeed, I always have to laugh afterwards how much effort we put into trying to detect, let alone observe, these objects. Still, when you know you've seen something millions of light years away with the naked eye and some glass it's always a bit of a moment. HCG61 was probably my fav, that looked wonderful. I am having nagging doubts now I was even lined up on 51 and 57 as I definitely saw 79 which seemed brighter, but Vogel says it's much more challenging...

I'll have to wait to pick this up, HCG57 will probably be the first one I can see in autumn skies.

To be continued :) 

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I think having doubts over observations is very much part and parcel of observing towards the edge of what the conditions / scope / observer can deliver. Thats what sends us back out again !

Interesting how often the "2nd time around" is so much easier though :icon_biggrin:

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4 hours ago, John said:

I think having doubts over observations is very much part and parcel of observing towards the edge of what the conditions / scope / observer can deliver. Thats what sends us back out again !

Interesting how often the "2nd time around" is so much easier though :icon_biggrin:

At the time, I'm thinking 'got it'! Then even after jotting down notes etc, a week or two later I start thinking was I wanting it to happen, or did I really see it? From my limited experience, totally agree, second time around should set things straight. I'll try the 20mm APM to locate, given the much larger FOV and exit pupil. My GOTO is generally close but not always spot on within the inner 1/2 of the 20mm, so at 13 or 9mm, even with 100deg EPs, I can easily start hunting in the wrong direction. Especially given the scope can settle in the ground even a few mm as the night progresses and move things around!

2 hours ago, Captain Magenta said:

I’ll be getting Robert’s 500p when his wife sticks it on eBay 😉

Fortunately she doesn't use ebay! After the 500p was gone, she'd put me on there as a free sack of fertiliser, collection only, haha

19 minutes ago, Epick Crom said:

Great report Robert! Now that's one huge light bucket you got there, sounds like a blast! Keep enjoying the night sky👍

It is a lot of fun when out under dark, clear skies. It spoils me, but the views... Ironically I find using 15x70 binoculars with filters on large extended objects is a blast as well. Even on tricky stuff like the Cocoon Nebula. So easy to scan the sky- I use them handheld unless really teasing out details on specific objects. Still, I like the ability of a scope to use much higher magnifications.

My plan was to find another 500p second hand at the right price and make a binoscope, but it would be a nightmare to transport and set up without driving a full size transit around.

I may dabble with EEVA on the 20", that would open up a whole new level. I need to save some money for a decent set up with filters however...

My main suggestion for people with binoculars or scopes of any size would be to head out to dark sky sites when possible, even if it's only once or twice each 'observing season'. 

I wish we didn't lose astro darkness here over the summer, I have a lot of catching up to do!

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Great report and unless in your location you can make something of the May dark sky period, a good conclusion to the season. I think as Gerry has mentioned, perhaps if you could pick up something like a Delos 8mm, the transmission gain, could be good to contrast with any subtle enhancement compared with your current eyepiece at a similar focal length on these testing subjects. 

 

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Great report. Those skies sound fantastic.

Just amazing what can be seen with the right telescope in the right location in the right hands. You packed a months observing in to one night!

Mark

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23 hours ago, scarp15 said:

Great report and unless in your location you can make something of the May dark sky period, a good conclusion to the season. I think as Gerry has mentioned, perhaps if you could pick up something like a Delos 8mm, the transmission gain, could be good to contrast with any subtle enhancement compared with your current eyepiece at a similar focal length on these testing subjects. 

 

Hi Iain! Yes I was thinking even something with a tiny bit more magnification would help - I've heard so many good things about the Delos, I have to try one. I might try once more this new moon and see if I can chase anything up!

16 hours ago, mdstuart said:

Great report. Those skies sound fantastic.

Just amazing what can be seen with the right telescope in the right location in the right hands. You packed a months observing in to one night!

Mark

Hi Mark, thanks very much! I wish I could have left the scope up and tried this again on successive nights. It would bolster confidence in what I did see and what I 'thought' I saw. I bet I was totally off on HCG 57 - if some of the were mag 13 they should have jumped out under those conditions. I bet the GOTO was slightly off after the scope settled a bit on the ground. Should have started with the 20mm and moved in from there... I wrote a list in advance, so was able just to punch them in the GOTO and slew over in fairly rapid succession...when it's accurate that is! :)

15 hours ago, Stardaze said:

Sounds superb, definitely makes me want to get to a dark spot. Some great targets too, enjoyed reading that. 🙂

Thanks very much, it was great to finally get back out under some really dark skies, makes such a huge difference.

2 hours ago, Captain Magenta said:

I guess two out of three ain’t bad 😉

I use 'averted imagination' to locate most of my targets! No it's a bit frustrating after the fact, I'm really doubting myself now on a couple. Ack well, something to revisit. I imagine after a solid ID on some of these, they will be easier to relocate in the future and pull some more detail from them. I have to really work for these, good stuff!

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