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Equipment Discussions >> Eyepieces

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GeneT
Ely Kid
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Reged: 11/07/08

Loc: South Texas
Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: Nigel_Choy]
      #4357973 - 02/02/11 12:12 PM

Quote:

Wow looks like Many of you like the TV ep: But Manu of you still haven't tried the ES one. Should I flip a coin to see which to buy?




If you are going to flip a coin, play it safe and go with Nagler.


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Rick Woods
Postmaster
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Reged: 01/27/05

Loc: Inner Solar System
Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: Nigel_Choy]
      #4357993 - 02/02/11 12:22 PM

Quote:

So basically everything is the same except the brands and coatings?

My final decision is I'm going for Televue Nagler 31mm type 5



Nigel,

If you can't do a direct compare, then I think this is your best bet. You'll pay more, but I think you'll be getting the best unit. The 31mm Nagler is really an amazing eyepiece. The other brands might be as good, or they might not; but I don't think they'll be better.
There must be some reason that the 31mm is the one everything else gets compared to. If I had to get rid of all my TV eyepieces, this would be the last to go, and even then they'd have to pry it from my fingers. For me, it's in the "Legendary UWA" category, along with the old Meade 14mm UWA.

Of course, I've been wrong before!


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Jack Day
super member
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Reged: 03/04/05

Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: GeneT]
      #4358165 - 02/02/11 01:33 PM

If you do decide to go the TV route, be aware that it does require a bit more infocus as I recall, so some scopes will/may not come to focus without some modification.

Edited by Jack Day (02/02/11 01:41 PM)


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Bart
Carpal Tunnel
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Reged: 05/28/06

Loc: Somewhere near Charlottesville...
Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: Jack Day]
      #4358217 - 02/02/11 01:55 PM

Notice that we are now quibbling over small degrees of quality between the two, if any. I say save your money and get the ESs. Your money will go further.

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jrbarnett
Eyepiece Hooligan
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Reged: 02/28/06

Loc: Petaluma, CA
Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: Bart]
      #4358356 - 02/02/11 02:51 PM

Were there any detailed head-to-head comparisons shared?

I think in the absence of methodical A:B comparative data, it's premature to conclude that differences between the two are "small" in degree.

I bought a 30mm ES 82 (still awaiting first light, unfortunately) over a 31mm Nagler Type 5 mainly because (a) it was cheap on sale, (b) I find it hard to detect on-axis image quality differences between *any* long focal length, lowest power eyepieces (very different than high power/short focal length eyepieces IMO) and (c) I've used the 31mm Nagler a gazillion times at club star parties (borrowed) but have never looked through an ES 30mm, and wanted to try something new.

Here, specifically, is what I'd like to see compared:

1. Lateral color
2. Rectilinear distortion (day and night)
3. Field curvature
4. Tone
5. Correction for edge of field astigmatism
6. Comparative comfort (eye relief, visibility of field stop)
7. On-axis image quality
8. Fit and finish
9. Relative value

If the weather cooperates I plan on borrowing another CNer's 31mm Nagler and first lighting my 30mm ES on Saturday at our first seasonal club star party and indulging my curiosity. If it works out, I'll share what I learn. If there's already a comparison of the two eyepieces with respect to these criteria, I'd love to give it a read.

Regards,

Jim


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sixela
Postmaster
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Reged: 12/23/04

Loc: Boechout, Belgium
Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: jrbarnett]
      #4358767 - 02/02/11 05:33 PM

Quote:


Here, specifically, is what I'd like to see compared:




I'll have a bite. The only caveat is that it's all daylight usage, so it sweeps a lot under the rug (the eye accommodates for quite a bit of field curvature for daylight targets, the eye pupil is restricted making the modified StarBlast eyepiece torture bench a benign scope, etc.).

Quote:


1. Lateral color




Appears to be the same as in long T5s (with the same sensitivity to eye placement in daylight usage). I expect the same ring of fire at night, but I haven't seen it yet.

Quote:


2. Rectilinear distortion (day and night)




Less. I guess the eyepieces are closer to zero angular magnification than the 31T5 is. Very noticeable in daylight use (but I used a 26T5 to compare).

Quote:


3. Field curvature



Seems quite flat for the time being (like the 31T5), but let's see at night. The eye knows all too well what you're looking at in daytime usage.

Quote:


4. Tone




Holding the eyepiece to a white wall, more neutral than the 26T5 and even the 16T5 (which is pretty white for a Nagler). Very similar to the 21mm Ethos.

Quote:

5. Correction for edge of field astigmatism



In a Paracorred Starblast, quite good compared to the 26T5, but of course the restricted eye pupil makes it easier on the eyepieces by lengthening the effective f/ratio well beyond f/4.6.

My guess (working from memory) is that it's slightly better than the behemoth Meade 5000 UWA, but conditions aren't favourable to really decide.

Quote:

6. Comparative comfort (eye relief, visibility of field stop)



Feels like a 26T5 (probably no coincidence, since they've abandoned the "innovative" eye cups at last and reverted to something which Just Works and has for ages).

I'd guess that makes the eye relief a tad smaller than that of a 31T5, but for me it's perfect. The 26T5 is stated to have 16mm of eye relief but the usable eye relief is't that large because of the concave eye lens, and this eyepiece shares all these traits. I have the eye lens at the exit pupil if I just press my face lightly on the eyeguard, so it's just perfect for me.

Quote:


7. On-axis image quality




I'm not sure you can say anything relevant for such eyepieces. In slow scopes, they're bound to perform well (essentially completely scope diffraction limited), and in fast scopes, at least my eye aberrations overwhelm anything an eyepiece can generate. In other words, there's no reason for me to prefer the 31T5; stars are going to appear just as ugly as with the naked eye anyway once my eye pupil is dilated.

Quote:


8. Fit and finish




External fit and finish superb, but coatings aren't as good as on T5s (and certainly not as on an Ethos). Coatings appear a bit more reflective but they don't "glow", so I don't expect a lot of low angle scatter, just somewhat less transmission (but we know from Brandons that's not that important) and perhaps some extra veiling glare (there are more chances for some of that light to creep back to the eye).

There are some shiny surfaces outside (retainer for field lens is a lip on the shiny barrel rather than a nice rounded and flat black retaining ring like on the 26T5, though I seem to remember it wasn't as wide on the 31T5) and inside (the one that's probably most troublesome is a grooved surface in the middle that is obviously anodised and reflects back to the eye both from the eye side and the scope side if you have a cap on the other side). My guess would be that it's going to be plagued by the exact same occasional "problems" as its predecessor, i.e. a rare problem with some extra veiling glare if you have very bright sources just outside of the view that might make it irritating for lunar observing, but for my scope type that's really not relevant.

Reflects a "what can we get away with if it costs less" attitude rather than the more paranoid attention to baffling in the Nagler (which in turn is just healthy paranoia, and nothing like the real paranoia Pentax or Zeiss can sometimes display).

Quote:


9. Relative value




No night time use, but I bet the eyepiece is good and daytime performance was really impressive for the price I paid. It's certainly light years ahead of the Meade 5000 SWA it replaces.


Quote:

If there's already a comparison of the two eyepieces with respect to these criteria, I'd love to give it a read.




I know what I wrote isn't perfect --daytime testing is only limited in what it can tell you, but hey, some imperfect info is better than none, right?


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Bart
Carpal Tunnel
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Reged: 05/28/06

Loc: Somewhere near Charlottesville...
Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: jrbarnett]
      #4358872 - 02/02/11 06:20 PM

Quote:

Were there any detailed head-to-head comparisons shared?

I think in the absence of methodical A:B comparative data, it's premature to conclude that differences between the two are "small" in degree.

Jim




You Sir are correct. I made my claim on anecdotal evidence and a few snippets of actual testing of the EP as presented by various folks that have handled the new line of EPs. My mistake.

I will say this, even if they are not equal to the vaunted Televue Nagle Eps, but in fact very close, I will still see them as desirable over the TVs at close to a third of their price. Half when not on sale. Its that magic balance between FOV, quality and cost that ES has met that has made a believer out of me. Bravo ES!

Now make a 2.7mm and a 21mm 82 and I will be in heaven, in more ways than one.

Cheers.


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GeneT
Ely Kid
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Reged: 11/07/08

Loc: South Texas
Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: Bart]
      #4359411 - 02/02/11 10:00 PM

Quote:

Its that magic balance between FOV, quality and cost that ES has met that has made a believer out of me. Bravo ES!




Cost is always a factor. One reason I buy TeleVue products is because I can afford them. I am not wealthy, but comfortable. Here is my saying: 'there may be eyepieces as good as TeleVue, but there are none better'. Now, this applies across all their lines. There are individual Plossls made by other vendors better than a specific TeleVue Plossl, and so on. However, their best are the best and their not the best are almost the best.
GeneT


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jrbarnett
Eyepiece Hooligan
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Reged: 02/28/06

Loc: Petaluma, CA
Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: sixela]
      #4359537 - 02/02/11 10:56 PM

Thanks Alexis. That's marvelous.

Very helpful.

Regards,

Jim


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sixela
Postmaster
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Reged: 12/23/04

Loc: Boechout, Belgium
Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: jrbarnett]
      #4359756 - 02/03/11 01:47 AM

I'd be interested to know if at least my daytime observations are consistent with what you see; two pairs of eyeballs are a better judge than one...

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Benach
Pooh-Bah


Reged: 01/24/08

Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: sixela]
      #4361362 - 02/03/11 06:39 PM

Alexis, will make an appointment for that within a couple of weeks ok? I still have the 31mm T5 so you then don't have to compare by heart but it can be done directly.

Edited by Benach (02/03/11 06:44 PM)


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jrbarnett
Eyepiece Hooligan
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Reged: 02/28/06

Loc: Petaluma, CA
Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: sixela]
      #4361688 - 02/03/11 09:04 PM

Hopefully Saturday, if the weather cooperates.

I'll be running a 4-incher though, and slow-ish to boot (f/8.6), so probably not as good of a test of edge correction as your Dob.

Regards,

Jim


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Benach
Pooh-Bah


Reged: 01/24/08

Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: jrbarnett]
      #4362455 - 02/04/11 09:08 AM

Jim: won't make it by next saturday. Will be somewhere in March though.

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sixela
Postmaster
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Reged: 12/23/04

Loc: Boechout, Belgium
Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: Benach]
      #4372732 - 02/08/11 05:21 PM

I've just had it under the stars. Compared it to a 26T5 and to a 21mm Ethos (which makes it harder for me to compare things like veiling glare because magnifications are different).

The scope in use was my resident eyepiece torture bench, aka Starblast with 2" focuser and Paracorr. An f/4.6 system with the Paracorr and an f/4 system without the Paracorr (but at that f/ratio unable to deliver clean stars because of brutal field curvature and coma, so it's only used to test specifically how much astigmatism is added when you subtract the scope aberrations).

A second scope (but used less intensively) was my Paracorred f/4.5 (f/5.1 with Paracorr) 400mm Dob.

Targets were the moon (for checking glare, scatter issues and lateral colour), M45 (for field curvature and astigmatism), the M36/37/38 open clusters in Auriga (for checking field curvature more stringently and for panning to discover what distortions there are) and M42 with NPB (with OIII/H-beta and H-alpha passbands, also to check on lateral colour).

Edge of field astigmatism is fairly well controlled, and only really obtrusive in the f/4 Starblast (where it combines with coma and field curvature but adds fairly obvious astigmatism from 20 from the edge onward). There's also quite a bit of field curvature in that scope but most comes from the fairly short focal length StarBlast.

With the Paracorr inserted, my eye's astigmatism actually dominates over the entire field (the vignetting by the secondary actually makes edge stars look less astigmatic than the centred stars!).

In the f/5.1 system, there is very little edge of field astigmatism, actually not much more than in T5 Naglers though more than at 40 off-axis in the 21mm Ethos (which is really a superb eyepiece).

There is too much field curvature too accommodate in the Starblast-sans-Paracorr, but I have no problem focusing the edge and the centre at the same time in even the Paracorred StarBlast, except when observing M36/37/38 critically (the eye accommodates less easily for different focus than on bright stars, and it takes the f/5.1 system with less field curvature on its own before no refocus at all is needed).

Colour tint is less yellow than in large T5 Naglers, still bluer than the fairly neutral 16T5 and very slightly more yellow than on the 21mm Ethos.

There seems to be little low angle scatter and the moon's ashen glow is actually just as well defined as in the 26T5 and 21mm Ethos.

There is some glare with the moon close to the field stop in the Starblast but none in my 400mm Dob (which is baffled better, and by the looks of it the Starblast's spider vanes are responsible for some of the issues and effects are visible even in the 21mm Ethos). No issues seem to be caused by the ring in the middle which in daylight seems to be a possible source of glare.

Distortion is very well controlled (at least for an 80 AFOV eyepiece). I'd say there is just a tad more pincushion distortion than is necessary to get zero angular magnification distortion but *a lot* less than in the T5 Naglers. Hardly any globe effect is visible when panning. Only the Ethos beats it even though there is actually more angular magnification distortion at the edge of the Ethos (but that's at 50 off-axis instead of 40).

Lateral colour is well controlled but starts fairly brutally at 7 from the edge (when placing the moon at the edge in the Starblast one end of the moon is a rainbow and the other end has no lateral colour at all). When using an NPB filter, stars also only split into a red one and a green one fairly close to the edge -- much closer to the edge than I remember in Panoptics let alone Meade 5000 SWAs. The T5 has the same kind of effect but much closer to the edge, and the Ethos is almost completely devoid of lateral colour except just next to the field stop.

Summary: darn close to a T5. It's very hard for me to evaluate whether the coatings actually cause more veiling glare because of the differences in magnification (and I suspect even 30mm ES vs. 31mm T5 might make it too close to call). A tiny bit more edge of field astigmatism but really insignificantly so in fast scopes because my eye is actually what gates performance. In an f/5 scope, though, I don't think it'd be that easy to see much difference in focus (though star testing should still enable you to see which is the 31T5). If one thing is different, it's the lateral colour that's absent from the majority of the field but pops up close to the edge.

Light years ahead of the 34mm Meade 5000 SWA it replaced.


For the price I paid, it's a killer eyepiece.


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mgb
sage
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Reged: 09/02/09

Loc: Montreal, Qc... Canada
Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: sixela]
      #4373070 - 02/08/11 08:00 PM

Sixela,

Thank you for this great report... Greatly appreciated.


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Paul R.
professor emeritus


Reged: 04/08/07

Loc: Northern Illinois
Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: FirstSight]
      #4373851 - 02/09/11 06:21 AM

Had them both for usage in a f5 scope. The 31N was far superior..better contrast, sharper, very little pincushion distortion compared to the 35P..etc..smaller exit pupil..

Plainly I could *see* things in the scope's field in the 31N that I couldn't see with the 35P. A no brainer here..

I have news for you though..the 21E for the most part outperforms BOTH of them..with the obvious exception of slightly smaller actual FOV and diminished eye relief.


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sixela
Postmaster
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Reged: 12/23/04

Loc: Boechout, Belgium
Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: Paul R.]
      #4374000 - 02/09/11 08:27 AM

Depends on the object.

A 21E is better to see detail in objects that in a 30ES/31T5 are well above the contrast threshold for detection, but if you have very large but very faint objects you do need larger exit pupils to increase the chance of detection.

That's why I have both a 30ES and a 21E.


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robinsondd
sage


Reged: 05/28/07

Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: Benach]
      #5249483 - 05/31/12 08:07 PM

Came across this thread will looking at the Nagler 31T5.

So Nigel, how do you like your EP?


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Scanning4Comets
Markus
*****

Reged: 12/26/04

Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: robinsondd]
      #5568661 - 12/13/12 04:20 AM

Wow!

Two excellent reviews Alexis! Both day and night versions were a nice read. I did a Google search on the 30mm ES N2 82 and ended up here reading ALL OF IT!



Very informative indeed.


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Damo636
sage


Reged: 08/16/11

Loc: Co Fermanagh, Northern Ireland
Re: TeleVue Nagler 31mm vs Explore Scientific 30mm ? new [Re: Paul R.]
      #5568724 - 12/13/12 06:44 AM

Quote:

Had them both for usage in a f5 scope. The 31N was far superior..better contrast, sharper, very little pincushion distortion compared to the 35P..etc..smaller exit pupil..

Plainly I could *see* things in the scope's field in the 31N that I couldn't see with the 35P. A no brainer here..

I have news for you though..the 21E for the most part outperforms BOTH of them..with the obvious exception of slightly smaller actual FOV and diminished eye relief.




Great reviews!

I also had both and did my own comparison. I kept the Nagler simply because the ES (latest N2 version) had completely unuseable filter threads! I found them so close at f5 its barely worth mentioning the differences. I don't know if its my eyes, but the 31 Nagler has the worst pincussion distortion I have ever seen! The ES to my eyes has a much flatter field. I have no doubt had the ES been in 100% working order, the Nagler would have been rehomed! I do love the big Nagler though & have no desire to part with it, unless maybe for the 25mm ES 100, if it ever comes to pass that is


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