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Rustysplit

35mm Panoptic in f5 dob

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I am having a bit of an EP crisis and have come to the conclusion that I much prefer the 68 deg fov to the wider fields. My eyes just seem to relax into the view better. Even my 72 deg 12mm Delos I find a little uncomfortable :eek:

I have a 27mm Panoptic and love it. I am using it in my 360/f5 dob. I would like a tiny bit more fov to frame such things as the Double cluster and M45, so I am very tempted to get a 35mm Pan to go alongside. My concern is the exit pupil size, 7mm. Do you think it would leave me with a washed out background ?

I know the sensible route is the 31mm nagler or es30, but eye comfort seems to discount these for me.

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Or what about the 41mm Panoptic? With an 8mm exit pupil this would surely be to much?

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hi Alan

I previously had a 12" f5.3 dob and a 35mm Panoptic. The combination was really good but as I have a fair bit of LP where I observe most (at home) and was going to swap to a f4 scope shortly afterwards, I went for the 26mm Nagler. The 26mm nagler is the best eyepiece I have ever looked through and gave me almost the same field as the Pan but with a darker exit pupil. I found from home this mattered more than at darker sites. If you mainly observe from a darker site I think the 35mm P would be a good buy.

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Part of the reason for building the dob was to get out to darker sites, so yes hopefully mainly under less polluted skies. It is really frustrating as my head tells me a Nagler is the clear choice. If only my eyes agreed.

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Alan,

I know my sky is very good and maybe as good as any you will find in the UK. I use a 35mm Pan very often in my 1000mm Mac/Newt giving an exit pupil about 7mm. The only time it causes concern it when it is not dark, like if I happen to look at the Moon as I am waiting for darkness.

So if you have a LP sky I would advise against the move as you tend to get the mirror shadow in the middle of FOV, but when dark no worries.

Alan.

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I think being able to see the field stop easily is a comfort thing for some people.  If the field of view is too large I think there's a temptation to allow one's eye to keep moving around it and then it's not so easy to just relax and look.  I don't think that happens for everyone, but I'm sure it does for some.

James

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Luke and Sarah (members here) were using a 35mm Panoptic with their 12" and then 16" Skywatcher dobs and felt the views with the Pan suddenly seemed "washed out" when they moved to a 21mm Ethos so I reckon an overlarge exit pupil is probably to be avoided to get optimum contrast on deep sky objects. 

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This is my concern John. It is a fair wedge of cash to drop if I get it wrong. I guess also I need to remember that for most objects the 27 is fine, and the 35 will be for the bigger targets and so probably not as widely used.

Alan, but under dark skies you find it ok?

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For big open clusters at dark skies....go for it Alan. If your using it at nice dark skies, it should be fine.

If you don't like the extra wide Naglers, stay with the Panoptics, as you know they're cracking eyepieces.

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Alan,

Yes I find it excellent, it is great for just looking at like a few weeks back, the star fields in Scorpius and the like, I would say it is the eyepiece I use the most, even when I use the LX and I do have the 41mm as well.

This is a bit too big in the M/N but I have given it a go.  I pay no attention to the exit pupil, I know it spills light but I just enjoy the very wide views, it's the secondry mirror that stops me using it.  I use the 41mm on the 115mm refractor and that is F7, I love it.

But you need the dark.

Unless it has to be Televue,  I found the 34mm SWA Meade/Maxvision a very close runner-up, think about it.

Steve, "Cracking eyepieces" not a good idea.

Alan

Edited by alan potts

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Sort of considering the ES 34mm 68. But as my mate Si pointed out, I will always feel that I should of got the TV. Damn their superb optics!! :smiley:

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Alan.

You could always buy the Meade one, it has black and green on it.  Go dig deep and get the 35mm Panoptic, I can't see you regreting it, sadly for you, you don't see to many secondhand.

Alan

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Alan (rusty)

I also prefer to see the field stop in my EP's.

I recently picked up the 68˚ 28mm ES and to be honest I'm shocked at how well it performs! I was torn between getting the 34mm ES or the 28mm but went for the 28mm as I just didnt want any bother with balance issues when changing from a big 2" EP to a much lighter 1 1/4" mid power EP (maybe it would of been ok but maybe not?!).

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I agree with Mike - I had a try of the ES 30mm alongside my Pan 35mm recently and was amazed how close they are in performance. If I was strapped for cash I have no hesitation and get the ES - there's really not a lot between them. :)

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Maybe it will be worth waiting for a used 34mm to eventually show up? Its not as if you are struggling with a poor low power EP now. :)

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As John says, when Sarah and I moved from a 12 inch dob (F5) to a 16 (F4.4), it became obvious there was a problem for us with the 35mm Panoptic. It was very washed out for us, which was a shame, as it is a beautiful eyepiece. We then found out that the high exit pupil was the problem, thanks to SGL and John! :icon_salut:  I suppose it was still usable for the less faint stuff, but it pained me to see such a good eye piece not at its best.

We now realise the 35mm was also a bit washed out before in our F5 dob, even under darker skies than home at the SGL star party. At the time, we just thought that was what wide, low-power eyepieces were like.

Don't some people measure their pupil in the dark? (I assume with a touch of red light so they can see the measurement!). I definitely don't have barn owl eyes :sad:

Edited by Luke

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Ahh, interesting to hear your thoughts on the ES ones. Unfortunately it just makes the choice harder......

Mike, my scope is a diy copy of your Sumerian, so the balance issue I fully agree with.

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Thanks for the info Luke. Oh this is so tricky.

I really love the 27mm Panoptic, the 35 would seem a perfect companion.

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A while ago I was using a 26mm Nagler which was a beautiful EP even though it was 82˚ ! I've only used the 28mm ES from home a couple times but its been enough to stop me hankering after another 26mm Nagler, seeing that field stop just makes observing more relaxing for me. :)

Would love to see some pics of your scope Alan!

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Their is something about seeing the stop that prevents my eye from wandering around too much. I know a lot of people love the wide views, I wish I did, but I must be happy with what is most comfortable.

Here you go Mike, the build thread if you are interested. Finished pics on page 5,

http://stargazerslounge.com/topic/179535-14360mm-truss-dob/

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Don't some people measure their pupil in the dark? (I assume with a touch of red light so they can see the measurement!). I definitely don't have barn owl eyes :sad:

I asked the optician to measure mine last time I had my eyes tested.  Ok, it was dim in the room rather than dark, but any loss of accuracy there is probably made up for by the fact that it's being done by someone else.  He reckoned about 6.5mm for me.

James

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I use my 35mm panoptic extensively at dark locations. Intially purchased for use with my F10 8" schimdt cassegrain (58X), then my F4.9 12" flextube (43X). In this scope, it did appear to let a bit of light through, yet it provided me with some  unforgetable views, commanding a wide frame vista on Andromeda, orion nebula and the Veil.

I now use it with my F4.5, 14" scope, although the exit puil ought to be that bit bigger, I think 7.8mm. In the two occasions I have so far had the opportunity to use this scope, it somehow feels yet more effective, both as a finder and for observing. Perhaps in part because the focal length, 1600 is providing a little more magnification at 46X.

In this scope, I recently used it to look at the Pleiades, the double cluster, bode's nebula and the Veil (again at a dark location) and each requiring a wide frame. It provided in each case a very satifying view.

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One thing that sways me away from the Meade/Maxvision is the fact that I regularly use my Skywatcher coma corrector which acts as a .9 reducer. Great for an increased fov, but it speeds the scope up to f4.5. I think the difference between the meades and the pan would be quite noticeable then.

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Iain, you may have just made my decision for me, with the coma corrector in place, my scope has just about the same spec as yours. :grin:

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