Eyepieces - Less glass is more

It would be nice to hear Alvin and others mention their favorites on minimal glass high-end eyepieces in the 5-10mm range for 200+ mag galaxy/PN observing. He had liked Zeiss in the last couple years I believe. Besides Nagler type 6 selection, I have only one 5mm Tak LE in this category (and a drawer of cheap to mid-end plossels, rarely used). I would prefer quality contrast and optics to AFOV for this eyepiece.

This would most often be used in a 18" dob f/3.7 with paracorr for around 1950mm focal length starmaster. Would take Paracorr out for some of the less-glass cases. Lately besides remote galaxies I am looking at a lot more planetaries as well. I want whatever eyepiece it is to be quality and known reputation to be great deep sky usage.
Thanks in advance,
Marko

Marko,

My current collection for low-glass high throughout eyepieces are:

4, 6 and 10mm ZAO-II's
5, 7, 9, 12.5, and 18mm BGO's (Baader Genuine Orthos)
17mm TV Plossl (just got this for 25 bucks and haven't played with it yet)
25mm Tak ortho 0.965"

On my wish list is an 8mm AP SPL to replace both my BGO 7 and 9mm as I wanted something that would slot right between my 6 and 10mm ZAO-II's.

My wide field set includes:
6 and 10mm Delos
13mm Ethos
waiting for the 5 and 8mm Delos

Then the barlow is the TMB 1.8x ED

You took so long to reply I was wondering when you might get back to the computer. ... I hope you are feeling well ;-)
(Thanks for the quick reply) From above and your web page (which I should have checked first) I suspect 6mm and perhaps later 10mm ZAO-II would be a good fit for my current needs and I'll just have to keep my eyes open to find them.

Mark,

All the ZAO II are excellent I use them in the 48" all the time they are my workhorses . I have the set of ZAO II 16MM,10MM, 6MM and 4MM. but no eyepiece has the light transmission of the TMB supermono, I have the 5MM, 7MM, 8MM, 9MM and10MM, in my scope you can easily see the gain in light grasp of the TMB supermonos. If I were you I would try to get a low count Ortho or SuperMono in a 2mm exit pupil and 1.5 mm exit pupil that is what shows the Faint fuzzies the best from my experience.

Good luck they are hard to come by. APM Telescopes Germany is making a run of high in orthos now so check Markus out you might still be able to get on the list. Maybe Dragan will jump in here he is on the list.

Marko,

I'm another advocate for less glass. My current set of EP's, other than some Ethos & Naglers, also contain the UO volcano top orthos. (I prefer the VT's over the flat tops for comfort. Alvin did a comparison some years back and discovered that the flat tops may be a bit better in contrast and detail but I still prefer the volcano tops.) But I digress....

The University Optics Orthos are probably the best value for a quality minimalist eyepiece. If you were so inclined to buy them all, you can have a complete set of new UO orthos for less than $700 bucks! They're even cheaper on the used market.

But as good a value as the UO's are, I'd have to go for the TMB Supermonos. Undoubtedly, one of the best EP's available. Jimi is correct, now is your chance to get some new TMB's! Markus Ludes of APM Telescopes in Germany is doing a limited run of 4, 5 & 6 mm SM's. They're exactly the same as the past TMB Supermonos. Currently he is only offering 25 pieces of each focal length so you may have to act fast. I've put myself on the list for one of each. I'd really like to see him come out with something in the 8-12.5mm range but he needs commitments first. An 8mm and a 10mm (1.6 & 2.0 exit pupils respectively) would be ideal in my scope and I'd jump on them in a heartbeat!

Send Markus a PM if you're so interested. He's a member here on DSF. His username is apmtelescopes

And I totally regret selling my 5 TMB SMC's (4, 5, 7, 9 and 12mm) when I got what I needed in the ZAO-II's. My only issue of the TMBs is the correction in fast scopes, only the middle 50% is sharp...but that middle 50% is what I cared about anyways.

Back in 2007 GSSP at Lassen Peak parking lot, I was observing with Gottlieb, Wagner, and about 20 others (the rest was at Bumpess Hell) I observed 22 members of Abell 2065 with my 4 and 5mm TMB SMC.

PS: I actually just got on DSF when I saw your post...perfect timing... lol

Thanks Jimi and Alvin. The comment about nothing is as good for light grasp as TMB SuperMono seems curious following the ZAO II comment. Perhaps you feel the downside of the supermono is AFOV of 30d vs 43d or if not, what other aspect of the ZAO II makes it more desirable than the SuperMonos? The ZAO II is 4 element in 2 group and TMB is 3 element in one group so that seems to be the better light grasp mechanism (this after 10 minutes of quick research just now). Lets limit the evaluation to assuming the central area with radius of 1/3 to 1/2 of the total radius for the field is the area of interest for the same reasons Alvin commented on, I too agree that Im generally concerned with very center of view.

Per all the above great pieces of advice I feel it is time to order so I have contacted Markus Ludes in a private message since those may be available if I 'act now'. This has been something I have needed for a long long time so now is the time for action.

Thanks for your advice but I am still curious as to what I have asked for other viewpoints if they are not covered above you you gents already.

This is about squeezing every photon I can get and not so much about 'best for the money' (I should have stated that earlier).

Quote:

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Originally Posted by Marko

...what other aspect of the ZAO II makes it more desirable than the SuperMonos?...

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I could spend paragraphs comparing them, but it's best summed up as the SuperMonos have better transmittance, but the ZAO II are sharper when compared in the 48".

Other viewpoints? You came to the right place <g>. The differences among the various eyepieces that are easily seen in the 48" simply cannot be seen in my 25" or 30". I have a full set of UO volcano tops which rarely get used because, after extensive A/B comparisons with my Nagler T6 set, I can see no discernible difference in contrast, light grasp, or, for lack of a specific word, detectability of objects in my scopes. With all else equal, I prefer the wider apparent field.

Both Jimi and I do see the difference in his scope, and neither he nor I see the difference in my scopes. We have discussed this phenomenon ad infinitum, and a couple of years ago we asked James Mulherin for a professional opinion. His theory was that it's a matter of small percentage differences that yield a large enough absolute difference in the larger aperture to cross the threshold of detectabiity, while remaining unnoticeable in the smaller scopes.

Thanks Jim for a key piece of info that I was unaware of and seems reasonable. Having done shootout between my Nagler T6 5mm and Tak LE 5mm with 18" scope in very dark skies I and a fellow observer as well had a tough time feeling the Tak was a better view (to any noticeable level). That shootout was a while back and my observing has progressed somewhat since then. I'm still thinking I will pick up two high-mag SuperMonos (if I can get them) as the much smaller FOV will also help me better judge sizes for small objects.

Thanks for all the info and leads Gents.

Quote:

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Originally Posted by Jim Chandler

Other viewpoints? You came to the right place <g>. The differences among the various eyepieces that are easily seen in the 48" simply cannot be seen in my 25" or 30". I have a full set of UO volcano tops which rarely get used because, after extensive A/B comparisons with my Nagler T6 set, I can see no discernible difference in contrast, light grasp, or, for lack of a specific word, detectability of objects in my scopes. With all else equal, I prefer the wider apparent field.

Both Jimi and I do see the difference in his scope, and neither he nor I see the difference in my scopes. We have discussed this phenomenon ad infinitum, and a couple of years ago we asked James Mulherin for a professional opinion. His theory was that it's a matter of small percentage differences that yield a large enough absolute difference in the larger aperture to cross the threshold of detectabiity, while remaining unnoticeable in the smaller scopes.

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On the other hand, at GSSP 2009, five observers, including Jimi and I saw the difference between the ZAO-II, UO HD and Ethos (all 6mm) in my 22". The UO HD is between the ZAO-II and Ethos, but a little closer to the ZAO-II in light transmission and the ability to perceive additional detail. Jimi and I agreed that the difference between the ZAO-II and the Ethos is obvious. Lastly, one of the five was a beginner and even he saw the difference.

One of the object we were looking at was the triple galaxy system, NGC 6745 in Lyra.

These comparisons of high quality eyepieces don't necessarily have clear cut results. It's a classic "your mileage may vary situation".

By way of example, at TSP the year Televue introduced the Ethos, Al Nagler was wandering the upper field with the Ethos 13mm in his pocket. Jimi, Mike Sowell, and I were using my 25" and Al came by and said "try it". We popped it in and looked at M13, were impressed by the contrast, and proceeded to compare the 13 Ethos with my 13 T6 Nagler. All three of us saw a clear improvement in contrast and brightness in the Ethos. We were impressed, to say the least.

After the Ethos 13 hit the market, I acquired one and used it extensively over a period of months, frequently comparing it to my 13 T6. The results? Maybe 1 object in 10 or 20 looked better in the Ethos, another one looked better in the T6, and the vast majority of objects looked pretty much the same in either eyepiece. In the intervening years, I've done the same comparison in the 18" and the 30" with pretty much the same results. No "aha" moment; just a lot of head scratching.

Totally agree. But small difference. I have never seen the T6 nagler outperform the Ethos. In some cases the view is the same in some objects with different eyepieces etc. ive even commented on CN that for brighter objects, the difference is not detectable. But, I've found that the difference is detectable in threshold objects where the low glass comes in really handy, where I do most of my observing.

PS: hope this came out right as I'm traveling now and using my iPhone to write this post.

All great info Gents and thanks for your comments on this topic that I knew beforehand was for some a curiosity and for others a topic bordering on 'religion'. I'm on the wait list for the 4mm and 6mm SuperMono cause 'I gots ta no'. I also don't have any 4 or 6mm eyepieces so it also rounds things out for the collection that needs some new blood anyway. It may be quite a wait before they are actually made but again, all in good time and no real rush.

I recently acquired a collection of older, simple 1.25" eyepieces. In this collection were some Brandons, a UO Ortho, EDS Ortho and various Plossl type eyepieces. I compared them while observing planets, and truly could not detect any difference in all areas with respect to image quality. However, what I could detect was a huge difference in comfort and presentation. The modern eyepieces were just far more entertaining and as such, allowed for more enthusiasm in practice making the experience far more engaging and productive thus seeing more. Within a week they were all sold off on A/Mart.

I have not though used these types of eyepieces while viewing DSOs, and I am positive that there is definite truth to the OP's testimony. Following the laws of physics, this just makes sense. The basic premise is always the same. To 'get' something more, you need to 'give' something more. The less glass light has to travel through, the less chance there is for optical corruption. You can even these disparities through engineering and design, but in the end there will always be some degree of compromise of which can be observed.

Eyepieces are some of my favorite inanimate things in life. Their importance in contribution to the focused image can NEVER be overestimated. The eyepiece is the 'interface'..or connection between material and flesh. Its interpretation is that of the entire optical system; including itself. This is where the subjectivity lies...

[


After the Ethos 13 hit the market, I acquired one and used it extensively over a period of months, frequently comparing it to my 13 T6. The results? Maybe 1 object in 10 or 20 looked better in the Ethos, another one looked better in the T6, and the vast majority of objects looked pretty much the same in either eyepiece. In the intervening years, I've done the same comparison in the 18" and the 30" with pretty much the same results. No "aha" moment; just a lot of head scratching.[/QUOTE]


Wow, my experience comparing the Ethos eyepieces to Naglers have been quite different. However, I should announce that this was comparing them to type 4 Naglers. I found the Ethos eyepieces to produce better contrast, sharpness, of course APOV..and in the end the greatest delta was in color neutrality. Objects just appear more 'color correct' giving the observer a greater sensation of observing unaided. I found them to be far better planetary performers as well due to this advantage. Maybe one day I will get a chance to compare them to a type 6 Nag.

Hello there;

Could one of the folks saying that they see a difference in viewing DSOs with a "simpler" eyepiece provide a precise observation. Tell me a faint galaxy or PN that you can see with an ortho that youi cannot see with a wide field modern eyepiece, please.

As someone said, this is a religious discussion and nothing is more personal than eyepieces. I have not seen any of the new and expensive eyepieces that provide a lot more detail than my three Panoptics and a complete set of Meade 4000 UWA's. But, that is just me.

Thanks;
Steve Coe

Quote:

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Originally Posted by stevecoe

Hello there;

Could one of the folks saying that they see a difference in viewing DSOs with a "simpler" eyepiece provide a precise observation. Tell me a faint galaxy or PN that you can see with an ortho that youi cannot see with a wide field modern eyepiece, please.

As someone said, this is a religious discussion and nothing is more personal than eyepieces. I have not seen any of the new and expensive eyepieces that provide a lot more detail than my three Panoptics and a complete set of Meade 4000 UWA's. But, that is just me.

Thanks;
Steve Coe

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Hi Steve,

Take a look at my page - scroll nearly all the way to the bottom. Look for the section titled "Going DEEP with simple eyepieces"
http://faintfuzzies.com/ObservingAids.html

If you are looking for something that is visible in a low glass count eyepiece versus an complex eyepiece. A recent example is Burbridge's chain with my friend's 22" reflector. The component I'm talking about is component D, MCG-4-3-12
http://www.astronomy-mall.com/Advent...e/burbidge.htm

And my observing report (scroll about 2/3 of the way down). This observation was confirmed Shneor, the owner of the 22". We used the 6mm ZAO-II. The other eyepiece we tried was the 6mm Ethos.
http://faintfuzzies.com/OR-Oct282011-SR.html


In regards of seeing the difference - it is mostly threshold objects or faint details where the difference is most obvious. When looking at eye candy or relatively bright objects, I could not see any obvious difference between the Ethos, Naglers, Panoptics, Delos, etc...

Thanks Alvin;

I appreciate the exact observation, just what I wanted. If I start chasing this type of fine detail I will consider a couple of high power, narrow field and simple eyepieces.

Of course, having Shneor Sherman confirm the observation is what really let me know it was legitimate. ;-)

Clear skies;
Steve Coe

You're welcome Steve. In regards to the NGC 6745 observation at GSSP, the five observers who saw the difference included Jimi Lowrey.

Quote:

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Originally Posted by stevecoe

Thanks Alvin;

I appreciate the exact observation, just what I wanted. If I start chasing this type of fine detail I will consider a couple of high power, narrow field and simple eyepieces.

Of course, having Shneor Sherman confirm the observation is what really let me know it was legitimate. ;-)

Clear skies;
Steve Coe

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It's a fact that Alvin's eyesight is better than mine...but if I could see it, you know that almost everyone could.
Clears,
Shneor

Have landed a 6mm supermono (1st run) eyepiece on AstroMart just now. Ordered a 12mm for the just announced next run that Markus of APM Telescopes announced on AstroMart a few days ago but I don't expect that one for a while. Having the 6mm by GSSP is important to me. Now to find an 8mm ... someday. 6mm gets me 1.6mm exit pupil and 8 would be a nice complement at 2.16mm (for no paracorr in 18" f/3.7). I realize the 2nd run and beyond have the better baffle but frankly one must jump on what one can find and the 1st run are reported as quite nice as well. I'll upgrade if my outstanding request to APM ever happens for that 6mm (and 8mm).

Now once they are all shipped to me I have 6,8,10,12mm. The ones I really wanted were 6,8 and I guess I got a bit carried away as I had to buy the 8,10 with a 'set' price on AstroMart last week too 'cinch' the deal. Except the 12mm that is a new run happening right now the others are all 1st gen versions. I would have rather had 2nd gen with better black interior but for the real dim stuff (my main purpose for these) I am hoping the 1st rev will be fine. I will only have the 6mm at GSSP as the 8,10 mm are going to be delivered WHILE I am at GSSP as they are coming from Australia. (dang). As Maxwell Smart would say 'Missed it by THAT much'. Oh well, I will have them for my Mt Lasson trip in August.

Am jumping on to the end of this thread. As it is pretty long, my apologies in advance if I'm covering old ground. Just don't feel like trying to filter through all the previous comments.

Am bringing this comment over from the OOTW thread in which Alvin referred to "high-glass eyepieces" (I'd never heard that description before). Which I now understand to mean basically premium wide-field EPs. Which is fine, I get it.

But am now curious if anyone's done the test comparing the Delos line to various low-glass alternatives.

Personally, I own all the Delos line except for the 17.3 (can't bring myself to part with my 17 T4 Nagler) plus the entire line of UO Orthos (volcano tops). I don't use the Orthos bare. I have a couple removable eye-cups that I use with them. Really helps with eye positioning and blocking local glare.

I never did a true A-B comparison between Naglers and Orthos. But in practice, there were many times I'd be digging on some HCG and be struggling to see something that should be there in a Nagler and would switch to an Ortho of equal FL and then be able to resolve the troublesome member. A prime example I do remember was going after UGC 4171 during TSP 2010 (part of Larry Mitchell's Flat Galaxies list). Had been using 9 and 5mm Naglers with no joy. Put in a borrowed 7 Ortho and it popped right out (looked like a field star developed diffraction spikes, but only along one axis). The 5mm Ortho allowed me to split the galaxy off of the star. That was pretty much my experience with Orthos v. Naglers. That was also the point that I really started looking for the "Nagler Alternative". That ended up being the Delos (couldn't bring myself to drop the big bucks on the Ethos but that's a whole other conversation).

I think the benefit of going to Orthos (or any other low-glass alternative) is two fold. The first is obviously less glass. But the other (and the one nobody talks about) is the tight field. Personally I find that my focus wanders a bit when using a wide-field EP. That soda-straw field of an Ortho really focuses me. My attention doesn't wander. But to really take advantage of that, tracking is absolutely necessary.

My experience with the Delos has been much more satisfying than with the Naglers. I feel like I'm seeing what I should be seeing when observing HCGs. So I haven't been using my Orthos. I think I'll have to do some testing this coming dark window. I wish I'd thought to go after UGC 4171 while in Pettigrew this past February. That'll make a nice test for the Delos.

Lou,

I've compared the ZAO-II and BCO to the Delos.

The 6mm ZAO-II versus 6mm Delos is here. It is repeatable over several nights.

I compared the 10mm BCO to the 10mm Delos along with my 10mm ZAO-II only once and found that the BCO slots in between the ZAO and Delos. I have not repeated it yet as I hadn't gotten a chance since.

Hope that helps.

Some years ago when Jupiter was at opposition and the seeing was near perfect I got stunning views through a 14.5 inch F 7 dob using a 13.8mm Meade Wide field eyepiece. My club members were lining up for the view of cloud bands so pronounced that they looked brown. Yet on putting in a 13 mm Nagler the view was pale and washed out by comparison, and at the time I thought that the extra glass in the Nagler was to blame.

Alvin: Your link is a wonderful page but it is not your 'high glass' study, it is a bunch of hicksons. Nice page but not on point. I know you have a great study on the issue but it may be some other link on your awesome website I think.

Lou: The reason Alvin started the reply with LOL on the other thread you linked to here is that Alvin is from what I have seen the #1 proponent of the virtues of eyepieces with as few lenses as possible. His comment on 'high-glass eyepiece' only refers to the Naglers and Ethos in that those designs have quite a few elements and not so much because they have a wide field of view.

The argument is the more glass surfaces, the more loss of signal from light hitting discontinuities and leading to reflection and interference loss and it all adds up.

The Zao-II are 'best of the best' and extremely rare and as such extremely expensive on a cost per gram of 'glass' ;-)
Others that have come up include SuperMonocentric eyepieces that are a very basic and extremely low lens count eyepiece.

It is for the reason that Alvin has studied this so much that I seek his expertise and opinion on this issue from time to time.

How do the Delos eyepieces stack up against these simpler eyepieces? I like the big eye lens and 20mm eye relief of the Delos. What about Brandons? Brandons have great contrast, but I'm not sure of the light transmission level. I use both of these.

Quote:

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Originally Posted by FaintFuzzies

On the other hand, at GSSP 2009, five observers, including Jimi and I saw the difference between the ZAO-II, UO HD and Ethos (all 6mm) in my 22". The UO HD is between the ZAO-II and Ethos, but a little closer to the ZAO-II in light transmission and the ability to perceive additional detail. Jimi and I agreed that the difference between the ZAO-II and the Ethos is obvious. Lastly, one of the five was a beginner and even he saw the difference.

One of the object we were looking at was the triple galaxy system, NGC 6745 in Lyra.

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Okay, I find all the optics and less glass is more idea interesting, and believable too. But I have one question for you fast dob owners. How much light do you lose from the Paracorr? I understand fast mirrors are necessary since you gotta transport a scope, but if you were looking at a observatory setting, would you consider going with a slower mirror such as f/5 ? The dobs I have owned were f/4.5 and f/6. At f/6 I didn't feel I needed a Paracorr. But it was a 10in scope, a 20in at f/6 would be huge.

Preston,
I have used Paracorrs for most of my observing years with f4.5 dobs and never once considered light loss. My main concern was for optimizing the observing experience and having objects and stars sharp to the edge. I figured might as well get the best experience possible. I found that I did not need a Paracorr with a 20" f5 dob but now am back again with a faster 22" f4.2 telescope. The effective f now is 4.8.
Whether transporting or having the telescope in an observatory, longer focal ratios also mean taller ladders.

Quote:

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Originally Posted by Preston Pendergraft

Okay, I find all the optics and less glass is more idea interesting, and believable too. But I have one question for you fast dob owners. How much light do you lose from the Paracorr? I understand fast mirrors are necessary since you gotta transport a scope, but if you were looking at a observatory setting, would you consider going with a slower mirror such as f/5 ? The dobs I have owned were f/4.5 and f/6. At f/6 I didn't feel I needed a Paracorr. But it was a 10in scope, a 20in at f/6 would be huge.

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Being a bit dated in some respects I have 6, 10, 16, and 25mm Clave plossls which I often use with a Clave Barlow, but on planets without the Barlow for max light transmission . Though over 30 years old they can still hold up well against many newer designs, though I sill like my Naglers and other wide fields.

The thread is digressing a bit but my main reason for 18" f 3.7 was no ladder at zenith and I love that advantage to this day. I zip around with fewer obstacles. When I go high mag which is how I tend to use the 6mm or 8mm eyepieces I am mostly only caring about the middle of the field as this is typically for tiny objects. I often take out the Paracorr for going real deep as it turns out the need for it is mostly for when you are using more of the light cone like 16mm or more. So I take it out and as such light loss (whatever it may be) is out of the picture (literally). I'm no expert on this but that is what I have heard and it seems reasonable. Everything is a tradeoff. If I only used it in a fixed location your argument seems reasonable and sure, 4.8 would offer a better view. For me, a ladder in the van is one more piece of stuff in there and one more thing to forget and be real sorry I forgot.