Stephan's Quintet

[David Levi]

I feel a bit guilty about the title for this thread in that it may be regarded as "click bait". I'll tell you now, I didn't see Stephan's Quintet while observing last night. It was a bit of a disappointment. Desperate to get some good observing during the new moon, on the spur of the moment, as the weather forecast became more certain, I drove two and a half hours to the Elan Valley. It's the first time that I have been there and it is a little bit darker than the Brecon Beacons. Having said that I think that looking straight up, there doesn't appear to be much difference. Perhaps the Milky Way is a bit more immediately obvious in Elan Valley but the real improvement comes low down towards the horizon. From my observing site in the Beacons there is quite a bit of horizon glow towards the south from the South Wales Valleys and to the north from the town of Brecon. At Elan Valley there's no light pollution. It's also more remote and a lot quieter traffic wise, no cars passed last night between 9pm and 1am. I say quiet 'traffic wise' because the roar of the water falling over the reservoir dam was very loud.

A week ago I had failed to see Stephan's Quintet, the galaxy cluster in Pegasus just below the galaxy C 30 (NGC 7331), while observing in the Brecon Beacons. Last night with the slightly better skies in the Elan Valley I was hoping that I would manage to see the cluster. Second time finding C 30 was no problem and using Stellarium I was able to exactly pin point the position where the quintet should be - only it wasn't there. I could see 3 magnitude 10 stars forming a reference triangle and a couple of 12.5 magnitude stars in the vicinity of the galaxy cluster's location but no fuzzy light. I think they must be too diffuse for my telescope aperture. My point in writing this report is to voice my doubt that the cluster is visible with a SkyWatcher Explorer 200P telescope. I used 59x, 125x and 200x magnifications, averted vision and moved the manual motion controls forwards and backwards to see if I could make out a contrast change with no luck. I'm not an expert on 'seeing' but I managed to see the A, B, C, D, E and F stars of the trapezium in The Orion Nebula last night the clearest I have ever seen them. E and F stars were pin point sharp at 125x magnification and I used this as confirmation of what I think to be true, that the telescope is collimated well (I didn't do a star test).

I would be interested to know if anyone has seen Stephan's Quintet using this telescope or any 8" telescope for that matter.

 

[alan potts]

I have seen the group with my 12 ich here from a dark site, whilst probably not as good a site as you mention I feel 8 inch is maybe close to the limit on this target. Was not that obvious even for me though, much better with the 18 inch. I will try with my 190mmM/n next time out using high accuracy slew, bit grey at the moment.

[jetstream]

My 200mm f3.8 dob shows them.

[David Levi]

1 minute ago, jetstream said:

My 200mm f3.8 dob shows them.

That's interesting and the sort of information I was after. Is that better optics, better atmospheric conditions or more experienced user? After last night I thought that I was through with Stephan's Quintet (I've spent enough time on it already) but after your comment I might pop back now and again just to check up on it.

[jetstream]

Keep trying David, this is a very tough object and needs great transparency. I find it "fussy" for mag in some scopes and use a zoom or zoom/barlow to nail it down and then switch to orthos. These galaxies are "ghost like" in appearance to me. Your 8mm Delos is the EP I would use and try with...

How is your dark adaptation? If you are not fully dark adapted forget it... after all "all cats are grey in the dark". If the sky looks dark at a dark site you are not dark adapted IMHO.

http://www.reinervogel.net/index_e.html

 

[David Levi]

I thought that my dark adaptation was good but there must remain a doubt over it after using Stellarium. I took precautions - pc set to minimum screen brightness and night mode, Stellarium set to night mode and a red acetate sheet placed over the screen. Now I know where to look I won't have to use a pc the next time.

What is the effect, if any, of your faster telescope Gerry @jetstream? Your f3.8 to my f5.

[jetstream]

When I observe DSO I do not use any light or look at bright objects, monitors are very bad- if I look at a computer screen it really wrecks my eyes for the dark. Could you see your scope/eyepieces/ground when dark adapted? I don't need light to change EP's etc and I memorize the object location prior to observing with my manual scopes.

The 200mm f3.8 will give more mag/illumination level and I must say this scope is not designed for faint galaxies but large diffuse emission nebula. Many eyepieces operate better at your f6 than the f3.8. My 10" f4.8 does well on Stephans Quintet too.

I wonder if @scarp15 has observed them in his 200mm f6?

[jetstream]

From Mels site

" I've been enthusiastically observing for a number of decades. Here are the factors that influence what I can see that night through the eyepiece of my telescope.

• Focal length gives you scale; it's important to understand the role of magnification. Check out my article on magnification.
• Aperture increases visibility and detail not only because of greater light gathering power but also because the greater magnification brings the object in closer.
• Seeing the object in a larger scope then returning immediately to your smaller scope can result in a half magnitude gain.
• Observer experience is worth 2 magnitudes (I have a series of sketches of M31 from childhood onward).
• Observer variation is a half magnitude or more.
• Age matters a magnitude: young kids can see very faint stars; as we get older, our lens yellows and ability to detect fades.
• Knowing where to look and what to look for worth a magnitude.
• Averted vision is worth a magnitude.
• Dark adaption continues to produce increasing benefits for hours, ultimately worth maybe a half a magnitude.
• Field baffling is an overwhelming factor: the difference between nonexistent and fully baffled views can be worth magnitudes.
• Covering your head with a black cloth also yields improvements, perhaps on the order of a fraction of a magnitude.
• Time at the eyepiece is worth a magnitude (objects gradually become recognizable or detectable over a period of time, and then they fade after a prolonged period of continuous observing).
• Comfort at the eyepiece is worth a half magnitude.
• Rested eyes are worth half a magnitude. I often take short breaks throughout the night. Upon returning to the eyepiece I can see more until my eyes tire.
• Sky transparency is such an overwhelming factor; on rare perfect nights I’ve seen scopes perform as if they had almost unlimited aperture; let’s call superb sky transparency worth a magnitude or two.
• Filters are worth a magnitude.
• Visibility appears to correlate most with aperture, then apparent size (the greater the aperture, the greater the apparent size, limited by the full field of view).
• True binocular or two eyed viewing results in a half magnitude gain in stellar limiting magnitude and about a magnitude gain for extended objects. Check out Bruce Sayre's experiences building and observing with binoscopes over the many years. And check out the last four years of the Oregon Star Party Telescope Walkabout featuring binoscopes "

http://www.bbastrodesigns.com/visual.html

[alanjgreen]

David,

I feel that this object is a real challenge in a 8" scope from the UK.

Firstly, you need plenty of magnification (below x150 its hard to see/find. x200 would be my goto magnification for this object once you have the right area) - a "goto" scope is a real benefit on this type of object.

In the C11 from semi-urban skies, I got three very small faint objects in a triangular pattern - this is 4 of the 5 galaxies and one of these is a merging pair. From the countryside with the C11, I got 4 of the 5 and it was so much easier to locate at x100 as I could see the blurry patch to focus in on. It took the 20" dob to see two cores inside the merging galaxy.

I also think that November is not the best month for this object and that I have had more success in August/September.

However, keep trying the key is to locate the object in as low power as poss (at least x100-x150) then get up to x200 once you have it centered.

Alan

[David Levi]

4 minutes ago, jetstream said:

• Time at the eyepiece is worth a magnitude (objects gradually become recognizable or detectable over a period of time, and then they fade after a prolonged period of continuous observing).

 

5 minutes ago, jetstream said:

• Rested eyes are worth half a magnitude. I often take short breaks throughout the night. Upon returning to the eyepiece I can see more until my eyes tire.

Excellent tips. I've picked out these two as ones that I recognize and while the second one seems natural, I have experienced the first one quite often (last night for example) without understanding what was going on.

Apart from setting up the telescope or dropping an eyepiece cover I usually never use my red light. I can even pour my tea from the flask into the cup without spilling a drop!

 

[Wiu-Wiu]

I've tried it in sqm 22 -ish skies with a 12" and I didn't see all five of them. I saw 3, but that is including a pair that I couldn't dissolve or recognise as 2. 

 

[Moonshane]

I agree that even with a dim red light your adaptation is affected. Less than with a screen though. Naturally as with most things there's a compromise somewhere 

[mdstuart]

I agree more magnification say 250 for those small galaxies. I can see them in my 16 inch from home but they are tough.

Try to see the small galaxies near 7331 as well.

Mark

[observer]

I think it will be a tough target for 8" as except for the NGC7320 all the other galaxies are 13+ mag. So really dark, transparent sky and good dark adaptation may be critical. If you study the map carefully before observing session you can avoid using PC-screen in the field as locating NGC7331 (C30) is easy,  the Quintet must be in the same field of view in low power eyepiece. Knowing the map you can then boost the power on target.

Using 10" scope last August I've managed to see only 3 fuzzy objects (NGC7318A+B as one) but the atmospheric conditions were far from optimal and the highest magnification I was using was 127x.

I think you should give it a try again when Pegasus is high in the sky.

Ivo

[scarp15]

Very interesting thread, I have only attempted Stephens Quintet with my 14" dob and my short-coming was perhaps in not applying enough magnification. A good heads up to revisit NGC 7331 and to perhaps give this a go, as I have placed little emphasis for a dedicated attempt to observe this galaxy cluster. Therefore, in response to Gerry's suggestion, I would not really know how an 8" F6 in UK conditions would perform, I expect though that it would be challenging. You do have access to some of the best of UK skies David, perhaps it might be worth your while considering joining the dob mob next time they plan on venturing across to Elan Valley as and when Stephens Quintet is still prominent. As indicated by your approach to observing particularly challenging subjects, although the 200p is capable of a great deal, perhaps it requires to be complemented with a 12-14-16 or 18" dob at some point. Seeing difficult objects in a larger aperture scope enables you to go back to the smaller instrument and competently successfully observe. An aspect, I consider that at times can assist is to sit or perch in comfort on an adjustable observers chair. A final thought, probably a trip to Gerry's, the problem is there's a chance you may not want to come home.

[estwing]

Good on you for making the effort...you'll be surprised how much is possible with the 8" at Elan...clear skies!

[swamp thing]

1 hour ago, estwing said:

Good on you for making the effort...you'll be surprised how much is possible with the 8" at Elan...clear skies!

^^^ This

Good on ya buddy for getting to dark skies  

It is well worth the effort. 

Have fun out there.  

[Littleguy80]

On 19/11/2017 at 13:50, jetstream said:

• Field baffling is an overwhelming factor: the difference between nonexistent and fully baffled views can be worth magnitudes.

Hi Gerry. What’s field baffling? I don’t think I’ve heard that term before!

[jetstream]

3 hours ago, Littleguy80 said:

Hi Gerry. What’s field baffling? I don’t think I’ve heard that term before!

As a real fan of newts we must look at some issues to maximize them, where my 15" is superb from Astrosystems, my 200mm f3.8 not so much- but it is now. An inherent advantage of refractors is the contrast they provide being unobstructed and easily baffled.

And then there's newts ...blowing light off the secondary mirror edged and holder, shiny primary mirror clips and the bevel and stray light entering the tube off axis blowing more light all over. Light entering from behind an open mirror cell can contribute to reduced contrast as can the steep light cone from fast mirrors glaring in the focuser tube...

This is a big topic and I don't want to hijack Davids thread.

Field baffling can be considered all those things mentioned including using an observing hood IMHO.My OOUK's need extension tubes on the front as I can see light shone through widefield eyepieces, off axis through the front of the newts. Getting great views is a process Neil, IMHO.

From Mel:

"Baffling is the single greatest improvement that you make to your telescope. Improve the telescope’s baffling until you cannot detect any glare through your eyepieces from a flashlight aimed at various angles at the telescope by a friend. Most important are the focuser baffle, the diagonal baffle and the primary mirror baffle. For more see my diagonal baffle calculator."

http://www.bbastrodesigns.com/TipsToImproveTelescopePerformance.html
 

[ollypenrice]

Our eyesight varies but, for me, 8 inches would probably be too small from my SQM21.9 skies. It can go from resonably easy to near impossible in our 14 inch or 20 inch. The sky has to be properly transparent without high haze and the moon right out of it. High elevation in the sky also makes a big difference.

I do think that using a screen of any kind would be bad news for my eyes but I can't speak for other people.

Doubtless you know this, but nodding the Dob on one axis can really make faint things pop.

Olly

[clarkpm4242]

I am sure that it is visible through an 8" scope from the Elan Valley.  A mate's 8" Celestron SCT on two separate visits.  He wasn't convinced though.

Good effort getting up to the Valley!  Watch out for icy roads!!

Paul

[jetstream]

I've tried different obstruction levels in the 200mm f3.8-about 32% and 38% and even with this moderate to high obstruction the 3 cores of the Quintet are caught in the eyepieces. The skies vary with the seasons giving a range from 21.5-21.8 SQM and a personal best NELM of 6.8 under the best conditions so far. The eyepiece most used is a Zeiss 25.1-6.7 with the VIP barlow and this combo give really good, but not the best (compared to some of my best DSO EP's) views.