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Who loves basic/simple glass eyepieces?

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#76 russell23

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Posted 25 February 2017 - 05:12 PM

Questions:  Do people have different opinions as to what constitutes "simple glass"?   I would consider any eyepiece with 5 or fewer elements "simple glass" - so the Mayusama and clones (Ultrascopics, Meade smoothie plossls, Parks Gold ...) would count as would my 40mm and 28mm XL's.   Is a simple glass eyepiece no longer considered simple glass if it is used with a highly transparent achromatic barlow such as the Dakin, or TV barlows?

 

Just wondering what people think.



#77 precaud

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Posted 25 February 2017 - 05:41 PM

Good question. I'm inconsistent about it, which suggests it is partially irrational. For sure, anything 4-element or less. Sometime I include the 5-element ones, sometimes I don't. I don't include the 5-element TMB clones. So apparently physical size matters but it shouldn't.

 

I'm inconsistent when it comes to barlows too. If its built into an eyepiece, it is included in its lens count. If it's separate, it is considered "added glass" but often ignored.

 

Fickle humaans.


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#78 russell23

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Posted 25 February 2017 - 05:47 PM

Good question. I'm inconsistent about it, which suggests it is partially irrational. For sure, anything 4-element or less. Sometime I include the 5-element ones, sometimes I don't. I don't include the 5-element TMB clones. So apparently physical size matters but it shouldn't.

 

I'm inconsistent when it comes to barlows too. If its built into an eyepiece, it is included in its lens count. If it's separate, it is considered "added glass" but often ignored.

 

Fickle humaans.

So maybe the quality of the glass or polish plays a role in our minds?   I don't consider the TMB clones as eyepieces that exhibit the performance characteristics that simple glass eyepieces are valued for.  Technically as 5 element eyepieces they are simple glass as I defined it earlier, but performance - while good - is not that which one expects from simple glass.



#79 Messyone

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Posted 25 February 2017 - 05:49 PM

 

I do. TEC turret with UOVT's 18 12.5 9 7 6. Not the 'best' ortho's but great views anyway.

 

Other simples are 2" UO 55mm plossl and RO 65XL plossl.

nice mount!  Is that homemade?  Looks like a TEC/Unitron hybrid.

 

Yes the mount is my own design and build...scope is an Istar 6" f12 objective and the rest I built to achieve the Unitron look I wanted.

 

Three years of my life I'll never get back  :lol:  In reality to own a large Frac and have it on a permanent very solid tall mount has transformed my observing experience, no more grovelling in the dirt and grass. 

 

Here is a link to a couple more pics  http://www.cloudynig...e-scope/page-39



#80 havasman

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Posted 25 February 2017 - 05:58 PM

I was completely surprised to meet the best success in my attempts to observe Q0957 +561 (PGC2518326), a mag 16.7 lensed quasar in UMa, via Ethos 4.7mm instead of KK Fujiyama HD-OR 12.5 and 9mm's w/ or w/o TV2x Barlow. It was confirmed by repeated attempts/observations through the very steady night last Tuesday.

 

The object was revealed as a dim point via averted vision, never held but repeatedly present. The larger field at high magnification gave me an easily recognized more relaxed eye that was straining to see the object.

 

So my most recent experience mirrors those in post #74 above.


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#81 CeleNoptic

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Posted 25 February 2017 - 06:09 PM

 

Good question. I'm inconsistent about it, which suggests it is partially irrational. For sure, anything 4-element or less. Sometime I include the 5-element ones, sometimes I don't. I don't include the 5-element TMB clones. So apparently physical size matters but it shouldn't.

 

I'm inconsistent when it comes to barlows too. If its built into an eyepiece, it is included in its lens count. If it's separate, it is considered "added glass" but often ignored.

 

Fickle humaans.

So maybe the quality of the glass or polish plays a role in our minds?   I don't consider the TMB clones as eyepieces that exhibit the performance characteristics that simple glass eyepieces are valued for.  Technically as 5 element eyepieces they are simple glass as I defined it earlier, but performance - while good - is not that which one expects from simple glass.

 

 

Than most of the TV eyepieces including Radians/Delites/Deloi should be considered "simple glass"? :grin:


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#82 leonard

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Posted 25 February 2017 - 06:41 PM

Hello ,


 

 

Quote:

Three years of my life I'll never get back  :lol:  In reality to own a large Frac and have it on a permanent very solid tall mount has transformed my observing experience, no more grovelling in the dirt and grass. 

 

 

      I must say  Messyone well done indeed !

One question , where is the mount keep , inside or outside and if outside how is it protected from weather ?

 

                    Thank You



#83 brisdob

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Posted 25 February 2017 - 07:55 PM

 

I think I may be rediscovering orthoscopics.  A few nights ago the seeing was really good and I had my old Vixen ED80S F9 out and just for fun was seeing how close I could get to the Dawes limit on close doubles.  With the 5mm and 3.5MM LVW's I was waiting for moments of still seeing to split them.  Just for fun I plugged in the 0.965 diagonal and 5mm Vixen ortho which came with the telescope.  They have just been sitting on the shelf for as long as I can remember, when I got the telescope the first thing I did was buy a Vixen 1.25" visual back.  The difference with the 5mm orthoscopic was quite staggering.  Very close doubles just sprang into view.  No more "ah wait, certainly elongated, ah there it is, nope it's gone."  Just clean splits.  Sorely tempted to pick up a few quality 1.25" orthos for high power.

Too bad you didn't have a 5mm LVW to make the comparison more relevant; apples and apples.  There's a big difference in magnification (and all of the evils that come with increased magnification) between a 3.5mm and 5mm eyepiece in most any scope.  Generally for double stars the best view will always be had using the longest eyepiece focal length that still allow you to see the split.  Planets are the same (i.e., the best quality view is with the lowest power eyepiece that still lets to detect the detail you're looking for).  

 

My experience has pretty much been the opposite.  When comparing identical or very close focal lengths, eyepieces matter very little on double stars.  There are a few poorly designs dogs out there (TMB Planetaries for example), but typically there's nothing I can't split in a Type 6 Nagler that I can in a Zeiss Ortho and vice-versa.  Now if double stars are your thing, that's actually really good news since old, simple eyepiece are very inexpensive and there's no advantage on such targets of buying ultra-wides.  On the other hand, splitting a given double with an 8mm LVW is a much more pleasant ergonomic experience than doing so with an 8mm Televue Plossl or TMB Supermono.

 

Regards,

 

Jim

 

Hi Jim, unclear wording on my part.  I was initially using the 5mm LVW and 3.5mm LVW and then plugged in the Vixen 0.965 diagonal and 5mm orthoscopic.  It has since occurred to me that when I decided to try the orthoscopic it was at that point in the evening, around 1 a.m or so, when the seeing was improving quite rapidly.  That may have been a factor as well.  I completely agree with your point about ergonomics - one reason why I have owned some of my LVW's for over 15 years now.  Realistically, as with many comparisons, there are a lot of variables at play; the seeing changing during the swap, change of diagonal, ergonomics, maybe even observer bias and expectations - changing an eyepiece and hoping to see a difference is hardly a double blind test!



#84 Allan Wade

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Posted 25 February 2017 - 09:53 PM

I was completely surprised to meet the best success in my attempts to observe Q0957 +561 (PGC2518326), a mag 16.7 lensed quasar in UMa, via Ethos 4.7mm instead of KK Fujiyama HD-OR 12.5 and 9mm's w/ or w/o TV2x Barlow. It was confirmed by repeated attempts/observations through the very steady night last Tuesday.

 

The object was revealed as a dim point via averted vision, never held but repeatedly present. The larger field at high magnification gave me an easily recognized more relaxed eye that was straining to see the object.

 

So my most recent experience mirrors those in post #74 above.

I have similiar experiences in the 12" viewing threshold objects. I can't see a difference in transmission between the orthos and wide fields. Alvin Huey seemed to indicate it takes big aperture to see the difference.

 

Where the orthos rise to the top, as far as I've seen, is in contrast and scatter control. In the 12", Deimos was a clear observation through the Tak Abbes and TMB SMC's, but completely invisible in the Delos, even though I knew exactly where it was.



#85 BigC

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Posted 25 February 2017 - 10:56 PM

Over the years I have been wooed by ultrawidefieldmegahyper eyepieces. Very intoxicating.
Then lately I've been enjoying a plossl or two, konig, erfle etc. nothing crazy like Zeiss ortho. They bring me back to my original observing thrills. Sometimes I think maybe a set of TV plossls would make me happy. My first TV eyepiece was an 11mm plossl bought for me by my late wife.
I fondly recall the "Woh!" I felt from the contrast.
Some amount of sentamdntality here but ....

Well, I now have over 100 eyepieces and oculars!(Oculars:what eyepieces used to be called;and I think it was a perfectly good name!)

 

Many simple ones like the Kellners, MA, and SMA included with inexpensive scope sets;also  wider modern glass of 66,82, and even 100 degrees.Then there are  a few RKE and Criterion of various designs.

 

Just had a tryout of 4 classic Criterion 1.25" oculars in my Celestron 150/750 reflector.18 AR,16.3 Erfle,9 AR, and 4 Ortho.Forgot to hunt up some of the others like 30mm ASP. All 4 tested well and trapezium seen as 4 stars in all. (Surprised how little power is needed to see the trap. as four stars on a night with good seeing.)

 

Anyway, I don't think the stargazers of the 50s and 60s were handicapped by good oculars being unavailable although the price in hours worked was much higher. The new wide views are nice but more of a luxury than a necessity.Since my eyepieces are typically bought only when at reduced price or bundled with a scope the total dollars invested  is much lower than you might think.

 

I find the old simple oculars of quality construction  to be generally lighter and brighter,well suited for classic  and small scopes. The big,HEAVY  wide view eyepieces demand a sturdy focuser usually found only on newer scopes .

 

The herd does need culling as certain modern eyepieces don't seem to perform as advertised. :(


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#86 MartinPond

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Posted 26 February 2017 - 12:09 AM

I'd call 4 elements or less "simple".

 

Considering how many types that includes....that's pretty generous.

 

The main thing I see for getting a smooth, contrasty center field

is minimizing the number of curved air-glass faces:

Just 2 air-glass curves:

 

Flat-faced (non 'Super') Plossls,

flat-front 1,2-Konigs(SMA as an example),

3-element aspherics,

Kellners...

Monocentrics

 

 

Then a little more complex but still 4 or less elements:

orthos ,

  curved-front 1,2-Konig ,

super-plossls (curve outer  faces),

RKE 

 

I think of it as "the minimum # of elements to get 45 degrees afov or more".



#87 Richard Low

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Posted 26 February 2017 - 12:19 AM

I love simple-glass fewer-element eyepieces as well as wide to ultra-wide field eyepieces. Widefield eyepieces are great for extensive deepsky objects while simple-glass eyepieces show better details on planets. Horses for courses.

 

Observed through my APM 152/1200 triplet apo at 350x to 450x magnification, the simple-glass eyepieces beat the XWs & Ethos on image contrast & light transmission for better planetary details.

 

Here are some of my simple-glass eyepieces:

 

Back row: TMB SuperMonocentrics

Zeiss Abbe Ortho II 

Pentax XOs, XPs, o-7

Front row: Televue Plossls, Brandon 4mm, Ball Lens, H-10mm, CZJ 10x

 

6901738976_4a5e064b60_c.jpg


Edited by Richard Low, 26 February 2017 - 02:20 AM.

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#88 bbqediguana

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Posted 26 February 2017 - 08:11 AM

Questions:  Do people have different opinions as to what constitutes "simple glass"?   I would consider any eyepiece with 5 or fewer elements "simple glass" - so the Mayusama and clones (Ultrascopics, Meade smoothie plossls, Parks Gold ...) would count as would my 40mm and 28mm XL's.   Is a simple glass eyepiece no longer considered simple glass if it is used with a highly transparent achromatic barlow such as the Dakin, or TV barlows?

 

Just wondering what people think.

I'd say 4 elements or less, and no Barlows. Ever. :)

 

I'd also extend my preference to only include compact designs - Plössls, Orthos, Kellners, Konigs, MAs, Monos, RKEs, etc. I'm not saying these are any better than more complex designs - I'm just saying I prefer them. I also like to stick with just 1.25" eyepieces for their compact form factor. I can go out in the field with my 6 simple eyepieces - 3 in each coat pocket, and I can observe any target my 8" SCT will haul in. No swapping out Barlows, different diagonals, adapters, etc.

 

I like to keep my life simple... like me! LOL!


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#89 MartinPond

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Posted 27 February 2017 - 09:14 AM

If you really want to go simple, there are the "archaic" EPs, like

Huygens and Symmetric Ramsden....at least, for a scope over F8.

 

Two elements, two glass-air curves.

 

I think the symmetric Ramsden is written off too quickly, and the

  shabby grinding for both types in those 'free with scope" sets knocks

   it back more than the design merits.  SR is often called "just a little better"

   than H, but it doesn't look that way in practice...

   The Plossl's poor cousin isn't too bad, and contrast can be outstanding.

 

I made a 10mm Symmetric Ramsden with coated plano-convex lenses,

 a bit more closely spaced than the common 'best' claim.  It's quite rich and sharp

 out to 40-45 degrees with an F8, and the center 35 degrees is even quite good at F5.

Good glass really makes a difference (not the window glass from the old kits). 

  

Just in case you want to go a 'commando' as you can!

 

The junker 20mm Huygens was pretty sharp, but was cut to ~30 degrees.


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#90 starcanoe

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Posted 27 February 2017 - 09:38 AM

Interesting point there Martin....



#91 Scott99

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Posted 27 February 2017 - 10:53 AM

I agree simple or minimum glass means no barlow, 4 elements or less.  But I think 5-elements get credit for being the "minimum glass" of the widefield or barlowed range.   There's also the eye relief factor, the Tak LE 5mm and 7.5mm are like "lazy-man" orthos, a little more eye relief and FOV, on nights of poorer seeing I'm good with them.

 

One night I spent time comparing my AP Barlow and SPL eyepieces against several 5-to-7 element eyepieces, Tak LE, Pentax XW, a couple others.  I was impressed by the barlow/orthos, they seemed to deliver higher contrast & less scatter than any other combination, even the 5 element ones.  

 

I theorized that maybe because the Smyth lenses are large in the Barcon vs. tiny in an wide-field eyepiece they perform better? 



#92 MartinPond

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Posted 27 February 2017 - 11:49 AM

Usually, the smaller inboard matched barlows work a bit better,

but if you have a well-baffled long outboard barlow....those can improve contrast.

I love the Tri-Mag.



#93 Peter Besenbruch

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Posted 27 February 2017 - 03:33 PM

Good question. I'm inconsistent about it, which suggests it is partially irrational. For sure, anything 4-element or less. Sometime I include the 5-element ones, sometimes I don't. I don't include the 5-element TMB clones. So apparently physical size matters but it shouldn't.

 

I'm inconsistent when it comes to barlows too. If its built into an eyepiece, it is included in its lens count. If it's separate, it is considered "added glass" but often ignored.

 

Fickle humaans.

I'm going to say anything 2 groups or less constitutes "simple glass." I don't really care how many elements. Using a Barlow adds one or two groups, and the Barlow must be factored into the simple glass equation. Nothing will alter my opinion. We all must be able to stick with fidelity to the purity of our definitions. After all, simple glass requires sacrifice.

 

disclaimer: If some company wants to pay me for my great expertise, "simple glass" means whatever "some company" says it means.


Edited by Peter Besenbruch, 27 February 2017 - 04:26 PM.

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#94 Scott99

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Posted 27 February 2017 - 04:08 PM

I'm going to say anything 2 groups or less constitutes "simple glass." I don't really care how many elements. Using a Barlow makes adds one or two groups, and the Barlow must be factored into the simple glass equation. Nothing will alter my opinion. We all must be able to stick with fidelity to the purity of our definitions. After all, simple glass requires sacrifice.

works for me!  with your definion one could even get away with using a barlowed Supermono and still be minimum glass.


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#95 lylver

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Posted 27 February 2017 - 04:53 PM

Barlow/Smyth group flatten the field and narrow incoming light angles. So with narrow angle, ghost, light scatter etc. are further easier to control, especially with some formula like plossl, kellner.

 

 

The X2 Clavé - f = - 113.4 mm

A Barlow lens of this type was calculated by Maurice Paul in 1935 for a 54 mm diameter (ref : Revue d'Optique Théorique et Instrumentale - Mai 1935 - Page 188). Latter on, Jean Texereau asked Clavé company in Paris to manufacture this type of lens in 27 mm size (1955). This design (Clairaut aplanetic doublet) is corrected from spherical aberration and is intended to correct the coma of Newtonian telescope with F/D > 5. Specifications have been re-calculated by Serge Bertorello for a 25.1 mm diameter based on the original Maurice Paul paper (see : http://serge.bertore...r/barlwmp.html)

In 1955 no one asked about not using it.

I don't think,at this time, there was very sophisticated eyepiece with short focal length and big eye relief.

 

Newton-450F5-Barlow-Strelh-compar.jpg


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#96 MartinPond

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Posted 28 February 2017 - 03:35 PM

Awesome chart!

 

I think the long distance to the Barlow (if you keep it long) leaves 

that glass out of the EP picture...but it is extra glass to the purist.  I understand.

 

Two things that you have to watch with a Barlow:

----keeping it's elements clean

----and especially, keeping the field lens of the EP very clean indeed.

Given that, it can be rewarding, but it does take a bit more Windex...or lighter fluid.

 

Using a 1,2-Konig at 10mm opens up the eye relief and usually keeps me

    from wanting the Barlow.  Thing is: if you pop in a 6-10mm Plossl and wipe it

    back-n-forth with your lashes...you won't get that pristine bare glass  experience.

 

If your scope has a long FL.....no problems going 'commando'.


Edited by MartinPond, 28 February 2017 - 03:36 PM.

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#97 Astrojensen

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Posted 28 February 2017 - 04:49 PM

My first really good eyepieces were orthos and the love stuck for many years and to some degree still does. A few years ago, I discovered the joy of wide-field observing with dobsonians, so I bought some GSO Superviews to test the waters. I was shocked by how sharp these were, for such cheap eyepieces! I bought three pairs, 20mm, 15mm and 10mm, for binoviewing, and when comparing the two 10mm's, I discovered that one of them was a little sharper and cleaner than the other. It was close to the equal of my 10mm Zeiss ortho, but with 70° AFOV and better eye relief. It was actually BETTER on faint deep-sky details, because it was much more comfortable in use.  

 

Now this was fascinating, so I ordered some ES82 eyepieces, a 30mm, 18mm and 11mm, and shortly after I was able to find a used 8.8mm. A little after that, I received a 9mm ES100 as a gift (thanks Gene!). Naturally, I wanted to compare them to my orthos. Frankly, the image quality is shockingly good! In my long-focus Zeiss achromats and apochromats I can hardly see a difference at all, in terms of sharpness and contrast, between the ES82's and my orthos. The 18mm ES82 is actually sharper than my 18mm UO volcano-tops... And the 9mm ES100 is sharper than all my orthos, save for a 9mm prewar Zeiss and on par with a Japanese 0.965" multicoated Kokusai Kohki ortho. Using my 63mm Zeiss Telemator as a test scope, the 9mm ES100 showed the dim companion to Vega better than the 9mm UO Volcano-tops, on par with the Zeiss prewar ortho and only topped ever so slightly by the multicoated 9mm KK ortho. Lunar views in the 9mm ES100 with the 63mm Zeiss are simply incredibly good. The whole Moon is ortho-like sharp and the field is almost twice as wide as the whole Moon.

 

But for planetary observing, I almost never use single eyepieces any more. I use a Baader Maxbright binoviewer on a Baader/Zeiss T2 prism diagonal, perhaps a 1.25x, 1.7x or 2.6x Glass Path Corrector (think of it as a barlow) and two 25mm Zeiss OPMI eyepieces, a 1-2-1 König design. That adds up to a LOT of glass/air surfaces and yet, I see more than I ever did with a single eyepiece. The 25mm Zeiss OPMI eyepieces are the finest 25mm eyepieces I've ever seen, bar none.  

 

But that doesn't mean I've never seen a ultra-simple eyepiece that beat anything else, even if my orthos and ES82's are virtually neck to neck. I once made an eyepiece, where the only optical elements was a simple achromatic doublet lens with 18mm focal length. It was housed in the barrel from an old 18mm plastic huygenian. Just a funny experiment, because I had read about astronomers using such eyepieces in the past. 

 

This eyepiece was SHOCKINGLY sharp and contrasty! The AFOV was only around 12° - 15°, probably closer to 12°, but the views were unreal. Especially solar details were absolutely mindblowing, once you could get what you wanted to see, into the tiny field. This was a huge problem, so I never used it much. Once I got my binoviewer, it was game over for this eyepiece, since I didn't have two of them. 

 

But I did use the binoviewer to directly compare it with my 18mm UO ortho. Funny enough, I could get them into focus at the same time and even look through both of them simultaneously! What I saw was completely shocking (again!) and jaw-dropping. This was a daytime test, and I was looking at a distant grain silo with some antennae on the top. Where the UO showed deep, black shadows, the achromat showed lots of faint details in the shadows. The difference was staggeringly obvious.

 

It has obviously occurred to me, that a Monocentric should be able to do the same thing, but they're pretty darn expensive, so I never got some. If I ever get the lathe, I've always wanted, I'll get some small achromats from Edmund Optics and build me some ultra special planetary eyepieces - and I'll make them in pairs, so I can use them in my binoviewer.

 

 

Clear skies!

Thomas, Denmark 



#98 noisejammer

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Posted 28 February 2017 - 04:52 PM

I have bought three pairs of Delos - they work well for me but critical eye placement makes them challenging for newbs. Ditto for my ES 92 series. I'll take them out in a dark corner but seldom in polite company. :D

 

My experience is that a limited field of view really doesn't matter when I'm binoviewing... I can only really see about 50-55° anyway. Masuyama 35's and Tak 30 LE's (occasionally Barlowed) do most of the work in my scopes. At higher powers, I have pairs of 7.5 and 5 mm LE's which are great and offer plenty of eye relief.

 

On truly exceptional nights I drag my ZAO II's out for a drink of ancient photons. I really enjoy using them but they are basically irreplaceable so I ration myself.



#99 walt99

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Posted 28 February 2017 - 06:16 PM

If I had ZAO II's ,   I believe I would wear them out !  smile.gif

 

 

Happy skies,  Walt




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