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Equipment Discussions >> Eyepieces

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Peter Natscher
professor emeritus


Reged: 03/28/06

Loc: Central Coast California
31 Nagler vs. 41 Panoptic new
      #5644288 - 01/26/13 12:06 PM

For my A-P F/8 175EDFS, I'm considering getting a 41 Panoptic vs. the 31 Nagler that I already have. The 41 Pany gives a better exit pupil (5.1 vs. 3.9) it widens the fov a bit more (1.9° vs. 1.7°), and has even more eye relief. Does anyone have any suggestions and experiences with their 41 Pany vs. 31 Nagler? I'm looking at issues like: eyepiece field curvature, distortion, light transmission?

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Paul G
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Reged: 05/08/03

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Re: 31 Nagler vs. 41 Panoptic new [Re: Peter Natscher]
      #5644309 - 01/26/13 12:23 PM

I can't imagine light transmission would be detectably different. I have both eyepieces, haven't tried the Pan in the 175 yet. Next time out I will and will try to remember to post my impressions here. Might be a while, a snowstorm moved through here last night, took me 2 hours to drive 20 miles home from work.

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Happy Birthday MRNUTTY
Carpal Tunnel
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Reged: 11/22/11

Loc: Mendon, MA
Re: 31 Nagler vs. 41 Panoptic new [Re: Paul G]
      #5644353 - 01/26/13 12:52 PM

More infos here 41 vs 31

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Starman1
Vendor (EyepiecesEtc.com)
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Reged: 06/24/03

Loc: Los Angeles
Re: 31 Nagler vs. 41 Panoptic new [Re: Peter Natscher]
      #5644415 - 01/26/13 01:30 PM

Quote:

For my A-P F/8 175EDFS, I'm considering getting a 41 Panoptic vs. the 31 Nagler that I already have. The 41 Pany gives a better exit pupil (5.1 vs. 3.9) it widens the fov a bit more (1.9° vs. 1.7°), and has even more eye relief. Does anyone have any suggestions and experiences with their 41 Pany vs. 31 Nagler? I'm looking at issues like: eyepiece field curvature, distortion, light transmission?



Field Curvature--minimal.
Distortion--no noticeable AMD, but RD is there, of course.
Light transmission--nice bright image (in the f/10 SCT)
Astigmatism--none
The edge of the field has a tiny trace of chromatic distortion in a tiny ring right at the field stop (it's green) but this can only be seen in the daytime or when the Moon exits the field (and it's much thinner than the color ring at the edge of the 31 Nagler, which is blue).
Eye relief--very long (27mm!). No problem with any glasses. For non-glasses wearers, the eyecup moves upwards almost a centimeter (or a little less), which might help position the eye.

What would you miss?
--the apparent field will seem small compared to the 31 Nagler.
--the lower magnification will make the background sky brighter. If you observe in very dark skies, this won't be an issue. If you observe in an urban or suburban setting, however, this may wash out some details in objects like the Orion nebula.
--the quality of star images. I don't know how old you are, but this major increase of exit pupil will definitely get you into the astigmatism zone, where your own eye is concerned. It is one of the reasons I didn't keep the 55mm Plossl when I owned an SCT, and it may affect your evaluation of the eyepiece.

Other than that, this is a top-class eyepiece, and doesn't really have many negatives intrinsically.


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Fred1
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Re: 31 Nagler vs. 41 Panoptic new [Re: MRNUTTY]
      #5644431 - 01/26/13 01:43 PM

That 41 vs 31 thread is a good one. I sold my 41Pan and 35Pan some time ago to buy the 31NT5 and have never looked back. That 8.29mm exit pupil in my 18" with the 41Pan was just too much (my secondary was visible if I didn't place my eye correctly) and the 31mm is, as stated in that thread, MUCH better edge corrected. However, I understand your thoughts, Peter, with the aperture/f ratio you have but do you really think you're missing much in that 12 arc minutes of additional TFOV?

Edited by Fred1 (01/26/13 01:46 PM)


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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Re: 31 Nagler vs. 41 Panoptic new [Re: Peter Natscher]
      #5644505 - 01/26/13 02:31 PM

A couple of years ago I was running the 40 XW against the 41 Panoptic and 31 Nagler. The Pentax was eliminated literally in minutes due to field curvature. Totally unacceptable for the money. (Of course people react to eyepieces sometimes in a personal way and the 40 XW has its fans.)

A bit more interesting was the 41 Panoptic against the 31 Nagler which took a few more months to play out.

Both are of course fine eyepieces, and at f/8 would be excellent. It really comes down to what one is after. Provided similar field stops, a design with a wider apparent field has an inherent advantage in being able to show similar fields at smaller exit pupils. The overall field is darker (both sky background and DSO) but the net effect is more pleasing to most people. The logical conclusion would be to go straight to Ethos, although I personally don't care for the 100 degree class eyepieces.

While the 41 Panoptic would give you slightly more field (quite a bit more if you calculate by area), how many large DSO's does it really make available? It sounds to me like this is what you are really after. Make up a transparency with scaled rings representing each field size and slide it across your favorite star atlas. You'll probably conclude that the number of discrete large DSO's is a pretty small number, and the "extra" DSO's the 41 Pan would completely show (vs. partial in the 31 Nagler) is counted on perhaps one hand?

In the end, I kept the 31 Nagler. The 41 Panoptic is really kind of specialist eyepiece for the very long focus scope, or where maximum true field trumps all else.

I should mention that I only use the 31 Nagler in my Dobs. With my AP Star 12 (f/8.5) I use a 48 Brandon in the low power role. Reason? I don't have a slide rail balance on the refractor, and changing from a 2+ pound eyepiece unbalances the scope and puts extra strain on the RA motor of my GM-8. The 48 Brandon performs very well at f/8.5, has a 38 mm field stop (very good true field), and only weighs 11 ounces.

Edited by Jeff Morgan (01/26/13 02:40 PM)


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Peter Natscher
professor emeritus


Reged: 03/28/06

Loc: Central Coast California
Re: 31 Nagler vs. 41 Panoptic new [Re: Jeff Morgan]
      #5644582 - 01/26/13 03:12 PM

I'm 62 and have a pupil size of ~6mm measured in my darkened bathroom -- so, the Pany's exit pupil is still 100% for me. I'm thinking the 41 Pan's larger exit pupil will brighten the image a dark site while observing nebula with narrow band filters. One thing though, my past 35 Pany used with a F/4.3 Dob showed a lot of field curvature. That was for a F/4.3 mirror. Would the 41 Pany do the same with a F/8 scope?

Quote:

A couple of years ago I was running the 40 XW against the 41 Panoptic and 31 Nagler. The Pentax was eliminated literally in minutes due to field curvature. Totally unacceptable for the money. (Of course people react to eyepieces sometimes in a personal way and the 40 XW has its fans.)

A bit more interesting was the 41 Panoptic against the 31 Nagler which took a few more months to play out.

Both are of course fine eyepieces, and at f/8 would be excellent. It really comes down to what one is after. Provided similar field stops, a design with a wider apparent field has an inherent advantage in being able to show similar fields at smaller exit pupils. The overall field is darker (both sky background and DSO) but the net effect is more pleasing to most people. The logical conclusion would be to go straight to Ethos, although I personally don't care for the 100 degree class eyepieces.

While the 41 Panoptic would give you slightly more field (quite a bit more if you calculate by area), how many large DSO's does it really make available? It sounds to me like this is what you are really after. Make up a transparency with scaled rings representing each field size and slide it across your favorite star atlas. You'll probably conclude that the number of discrete large DSO's is a pretty small number, and the "extra" DSO's the 41 Pan would completely show (vs. partial in the 31 Nagler) is counted on perhaps one hand?

In the end, I kept the 31 Nagler. The 41 Panoptic is really kind of specialist eyepiece for the very long focus scope, or where maximum true field trumps all else.

I should mention that I only use the 31 Nagler in my Dobs. With my AP Star 12 (f/8.5) I use a 48 Brandon in the low power role. Reason? I don't have a slide rail balance on the refractor, and changing from a 2+ pound eyepiece unbalances the scope and puts extra strain on the RA motor of my GM-8. The 48 Brandon performs very well at f/8.5, has a 38 mm field stop (very good true field), and only weighs 11 ounces.




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Starman1
Vendor (EyepiecesEtc.com)
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Reged: 06/24/03

Loc: Los Angeles
Re: 31 Nagler vs. 41 Panoptic new [Re: Peter Natscher]
      #5644787 - 01/26/13 05:31 PM

The field curvature of a scope is related to its focal length, not its focal ratio.
If the f/8 scope has a shorter focal length, it will exhibit more field curvature.

However, if the focal length exceeds 1000mm, the field curvature from the scope will be pretty small. If you see FC, it is probably from the eyepiece.

And, or course, on a short focal length scope, if the FC of the eyepiece and FC of the scope match in sign, then the visual FC will be a sum of the two, and the combination will be worse than either by itself.

This is the reason some people in some scopes object to FC in a particular eyepiece while other people in different scopes do not. Plus, obviously, the differing degrees of accommodation we all have in our eyes.


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Peter Natscher
professor emeritus


Reged: 03/28/06

Loc: Central Coast California
Re: 31 Nagler vs. 41 Panoptic new [Re: Jeff Morgan]
      #5644880 - 01/26/13 06:37 PM

There are lots of DSO's to observe at a local Bortle 3 and 2 dark site with my 7" APO. I would like to generously frame in a 1.5°+ field of view: large OC's, MW star clouds; narrow-band filtered Sharpless nebulas, large NGC's, IC's lying along the summer and winter galactic axis. My 175EDF F/8 might do very well with this kind of observing. Hence my initial interest in a 41mm Panoptic. Though no match with my 24" StarStructure Dob's light gathering ability, the 175 AP F/8 has very high contrast and definition capability. For instance, summertime Barnard's appear more pronounced (darker, contrasty, sharper, and more 3D) in the 175 than the 24" Dob. In the 175, would a 41 Panoptic better this effect over my 31 Nagler?

Quote:


While the 41 Panoptic would give you slightly more field (quite a bit more if you calculate by area), how many large DSO's does it really make available?




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Eddgie
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Reged: 02/01/06

Re: 31 Nagler vs. 41 Panoptic new [Re: Peter Natscher]
      #5644893 - 01/26/13 06:44 PM

I have both and have used them both in my 6" f/8 refractor.

I find them both to be flawless performers.

I get the argument for a bigger exit pupil, but it is an expensive price to be paid.

I find the 31mm to be far more compelling and use it for almost all observing (I use the scope primarly as a wide field telescope).

If you just wanted a bigger exit pupil for the occasional really dime DSO (Lagoon Nebula or similar) you can can get better results from a 55mm Plossl.

Anyway, both are excellent in my 6" APO, but I just like the view so much better using the 31mm. And the increase in exit pupil is not huge. Better to jump to the 55mm or 56mm Plossl if you want the maximum brightness the scope will produce. This will be a fairy large step in brightnss over the 31mm, while the 41 makes a slight difference, but not nearly as much as a 55mm Plossl.

My advice? Pick up a cheap used Meade 56mm Plossl for when you need it bright, and stick to the 31mm Nagler for most viewing. The view is so much more imersive in the 31mm than the 41mm that you will find that you don't use the 41mm that much. Just a hunch. I could be wrong, but it has been a couple of years since I use the 41mm in my 6" APO.

I use the 41mm all the time in my C14 though.


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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Re: 31 Nagler vs. 41 Panoptic [Re: Starman1]
      #5645185 - 01/26/13 09:51 PM

Quote:

And, or course, on a short focal length scope, if the FC of the eyepiece and FC of the scope match in sign, then the visual FC will be a sum of the two, and the combination will be worse than either by itself.




At one time I thought I read something about this in the old "Ask Al" column on the Tele Vue site. Unfortunately, these posts have long since vanished.

That would be a nice addition to a manufacturers list of specifications.


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Jeff Morgan
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Reged: 09/28/03

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Re: 31 Nagler vs. 41 Panoptic new [Re: Peter Natscher]
      #5645212 - 01/26/13 10:22 PM

Quote:

There are lots of DSO's to observe at a local Bortle 3 and 2 dark site with my 7" APO. I would like to generously frame in a 1.5°+ field of view: large OC's, MW star clouds; narrow-band filtered Sharpless nebulas, large NGC's, IC's lying along the summer and winter galactic axis. My 175EDF F/8 might do very well with this kind of observing. Hence my initial interest in a 41mm Panoptic. Though no match with my 24" StarStructure Dob's light gathering ability, the 175 AP F/8 has very high contrast and definition capability. For instance, summertime Barnard's appear more pronounced (darker, contrasty, sharper, and more 3D) in the 175 than the 24" Dob. In the 175, would a 41 Panoptic better this effect over my 31 Nagler?




Indeed, cruising the MW in the Star12 is breathtaking, and it has the same strengths you mention relative to my Dobs. Barnard objects are (usually) easy prey in the refractor, and it's a nice change of pace from double stars. In my case the Star12 only has 1000 mm focal length, so I have lots of choices to get fields over 2-1/4 degrees. The large IC clusters don't need aperture so much as field, with your longer focal length maybe the 41 would be best for you.


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Jon Isaacs
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Reged: 06/16/04

Loc: San Diego and Boulevard, CA
Re: 31 Nagler vs. 41 Panoptic new [Re: Peter Natscher]
      #5645461 - 01/27/13 04:28 AM

Quote:

For instance, summertime Barnard's appear more pronounced (darker, contrasty, sharper, and more 3D) in the 175 than the 24" Dob. In the 175, would a 41 Panoptic better this effect over my 31 Nagler?





My two cents:

At F/8, the 41mm Panoptic certainly makes sense, it's only a 5mm exit pupil and for objects that a best with a filter, that increased brightness can be very useful. As Eddgie suggests, a 55mm Plossl could be a useful addition as well.

I enjoy large fields of view, I am finding even the 4.5 degree TRoV of the 31mm Nagler in the NP-101 is insufficient for some parts of the sky, there are some amazing views to be had with 80mm F/5 with a 2 inch focuser, over 6 degrees. Add a 31mm Nagler and a O-III filter, it's a different world.

Jon


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Rinaldo
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Reged: 06/28/04

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Re: 31 Nagler vs. 41 Panoptic new [Re: Jon Isaacs]
      #5645474 - 01/27/13 04:48 AM

Simply put, I always preferred the nicer "picture window" view that the 31mm gave over the 41mm, even though the 41mm gave a bigger TFOV. The 31mm had more immersive~ness.

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