Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

So as ZAO Prices Head Into the Stratosphere I Wonder

  • Please log in to reply
520 replies to this topic

#451 Mcloud

Mcloud

    Mariner 2

  • -----
  • Posts: 231
  • Joined: 13 Aug 2014
  • Loc: Pittsburgh aka Gotham Cloud City

Posted 13 January 2022 - 10:24 PM

I would literally have to have money to burn to spend a grand on an eyepiece. I mean really at what point in the law of diminishing returns does that nice & bright green label equal or even exceed practicality or performance.
I've been in the hobby a little over 4 decades now. Back in the day you took those orthoscopic oculars and you liked them. The return of the slightly altered precipitation of the plossl what the first innovation I had.
In at honesty, so long as the eyepieces are of high quality, the only time I yearn for upgrades is when I read about what I have been missing. Again, full disclosure. I'm most likely never to afford any of the really high end eyepieces & I'm definitely jealous of those that can. 😂

#452 Sarkikos

Sarkikos

    ISS

  • *****
  • Posts: 34,444
  • Joined: 18 Dec 2007
  • Loc: Right Coast of the Chesapeake Bay

Posted 13 January 2022 - 10:37 PM

In a thread two years ago, among eyepieces for planetary still available new, BillP gave the Tak TOE's a ranking of 1b (class b in the top tier):

 

Best planetary eyepieces currently in production?

https://www.cloudyni...ion/?p=10761176

 

But the recent experience of bad QC would give me second thoughts.  Luckily, I bought a 4mm TOE a few months ago, and it was fine.

 

BillP's grading:

 

1a - Tak Abbe Ortho

1b - Tak TOE

2a - TV Delite

2b - Edmund RKE

2c - Tak LE

3 - Brandon

 

Mike


Edited by Sarkikos, 13 January 2022 - 10:38 PM.

  • turtle86, SandyHouTex, oldphysics and 1 other like this

#453 Jeff Morgan

Jeff Morgan

    Hubble

  • *****
  • Posts: 13,996
  • Joined: 28 Sep 2003
  • Loc: Prescott, AZ

Posted 13 January 2022 - 11:20 PM

The TOE's sound very good, and 10mm ER would be fine for me.  It's too bad that they aren't available in more focal lengths.  

 

Eyepieces like the Ethos are certainly expensive, no argument there, but some of us do like 100 degrees and that larger FOV really comes in handy when using an undriven mount.  So I don't really see the demand for that necessarily evaporating in 10 years.  (I do share your concern about light pollution.)

 

Then there's the Pentax XW.  One could still get three used XW's for the price of one used ZAO II.  The XW's are quite good on planets, and with their wider FOV are better for general DSO observing.  

 

And of course the ZAO II's are very hard to obtain at any price anyway, so there's that. 

 

I fully agree with your sentiments. If Tak extended that product line I would be snapping them up. They are that good.

 

Price/performance? Perhaps the central tenet of this thread. Again, I'm in agreement with you. I looked at all the factors and decided ZAO's are not on my shopping list. For now.


  • turtle86 likes this

#454 Sarkikos

Sarkikos

    ISS

  • *****
  • Posts: 34,444
  • Joined: 18 Dec 2007
  • Loc: Right Coast of the Chesapeake Bay

Posted 14 January 2022 - 08:37 AM

And wider fields of view are absolutely irrelevant to planetary and double star observing. 

A wider field of view makes star hopping easier.

 

If the mount doesn't track - and many if not most mounts used by amateur astronomers do not track - a wider field of view is convenient for all objects, including planets and double stars.  And although star hopping is not needed for finding and observing bright planets, it is needed for Uranus and Neptune if you do not have goto. 

 

Star hopping is often needed for finding and observing double stars.   

 

Many if not most mounts do not have goto.  I doubt seriously that all mounts will have tracking and goto in the future.

 

So are wider fields of view absolutely irrelevant to planetary and double star observing?  No, they are relevant in my experience.  Two of my most favorite eyepieces for planet and double star observing are the 3.7 and 4.7 Ethos-SX 110 degrees.  None of my mounts - that I still use - have tracking or goto. 

 

It really is wrong to assume that a large majority of mounts now have tracking and goto, and that all mounts in the future with have these features.

 

Mike


Edited by Sarkikos, 14 January 2022 - 01:07 PM.


#455 turtle86

turtle86

    Mr. Coffee

  • *****
  • Posts: 6,462
  • Joined: 09 Oct 2006
  • Loc: L2

Posted 14 January 2022 - 11:58 AM

I fully agree with your sentiments. If Tak extended that product line I would be snapping them up. They are that good.

 

Price/performance? Perhaps the central tenet of this thread. Again, I'm in agreement with you. I looked at all the factors and decided ZAO's are not on my shopping list. For now.

 

As much as I like using the 6 and 10mm ZAO II's, I don't miss the 4mm ZAO II at all.  

 

I suspect I would like the 4mm TOE much better.


  • Sarkikos and SandyHouTex like this

#456 davidgmd

davidgmd

    Viking 1

  • -----
  • Posts: 626
  • Joined: 24 Dec 2020
  • Loc: Maryland

Posted 14 January 2022 - 02:39 PM

 

So that leaves three viable astronomy options:

 

1) CMOS imaging from home - available every clear night, DSO’s look great;

2) Gen 3 Night Vision observing - available every clear night, DSO’s look great; and

3) Lunar, planetary, and double star observing - available every clear night.

 

How are the heavy, high cost, high scatter DSO widefield eyepieces going to fit into that future?

 

Not very well I suspect. In that environment people are going to realize very quickly that they do indeed hold detail better in well-made Orthoscopics and other real planetary designs. And no amount of “space walk”advertising bombardment in the astronomy magazines is going to convince them otherwise.

Hi Jeff - I figure as time passes, light pollution increases, and I get too creaky to feel like lugging the scope to a dark(er) site, option 2 might be my preferred choice.  Can night vision devices be used with existing eyepieces (e.g. on one side of the diagonal, or with a binoviewer)?  If so, would the scatter associated with multi-lens, wide-field eyepieces get amplified, accentuating the difference between them and minimal glass eyepieces?

 

I get that the field is limited by the NV device, but if I already had the eyepieces, would there be an advantage to trading them for minimal glass?


Edited by davidgmd, 14 January 2022 - 02:41 PM.

  • Sarkikos likes this

#457 Paul G

Paul G

    Cosmos

  • *****
  • Posts: 9,757
  • Joined: 08 May 2003
  • Loc: Freedonia

Posted 14 January 2022 - 08:22 PM

I agree.  It's not like the demand was ever that great to begin with.  If I recall correctly, the ZAO II's took a while to sell out.  They're great eyepieces but they're still a specialized niche item.

The ZAO I's, of which 400 sets were made (but way fewer of the optional 34 mm), 100 sets sold in the US, took over a year to sell out at about $260 each, but that was before the online hype about them. The IIs took a while as well, despite the online hype about ZAOs.

 

Same happened with the 2nd run of Supermonocentrics. Then, the final run of 50 pieces of each focal length were presold, but for a small number.  

The last regular run of the SMs took forever to sell out. Markus priced them at what he called "fire sale price" of about $115 IIRC and some focal lengths still took over a year to sell out. Markus blamed that on the review in S&T that found astigmatism in the eyepieces, said the sales immediately dropped to zero. Tom Back blamed it on saturation of a very small niche market in which 3000 of the eyepieces were sold. When Markus did small runs after that he required down payments before manufacturing because of his experience doing another run of the TMB 100 f8 refractor. He was besieged with requests to do another run of this superb scope, but once he did that turned out to be a lot of hot air and it took a long time to sell that batch.

 

Tiny eyepieces, with short eye relief and small fov, that give a small improvement in contrast under excellent seeing in scopes with excellent optics is a small fraction of an already very small market. I like the ZAOs, but I bought the Is when they were originally offered, so they were a screaming deal. I tried the SMs but the combination of small fov and very strong field curvature, given my age and my eyes' lack of ability to accommodate, resulted in a tiny soda straw fov, not my taste.


  • Moravianus, turtle86, Sarkikos and 2 others like this

#458 Jeff Morgan

Jeff Morgan

    Hubble

  • *****
  • Posts: 13,996
  • Joined: 28 Sep 2003
  • Loc: Prescott, AZ

Posted 14 January 2022 - 11:14 PM

A wider field of view makes star hopping easier.

 

If the mount doesn't track - and many if not most mounts used by amateur astronomers do not track - a wider field of view is convenient for all objects, including planets and double stars.  And although star hopping is not needed for finding and observing bright planets, it is needed for Uranus and Neptune if you do not have goto. 

 

Star hopping is often needed for finding and observing double stars.   

 

Many if not most mounts do not have goto.  I doubt seriously that all mounts will have tracking and goto in the future.

 

So are wider fields of view absolutely irrelevant to planetary and double star observing?  No, they are relevant in my experience.  Two of my most favorite eyepieces for planet and double star observing are the 3.7 and 4.7 Ethos-SX 110 degrees.  None of my mounts - that I still use - have tracking or goto. 

 

It really is wrong to assume that a large majority of mounts now have tracking and goto, and that all mounts in the future with have these features.

 

Mike

 

Hmmm.

 

Yes. If you like star hopping, that's great. But compared to DSC's, it is like tapping out Morse Code compared to using a keyboard. And that is probably a generous comparison.

 

A well made (that is to say orthogonal) mount can be equipped with encoders. Manual. Motorized. Doesn't matter. Drive systems are becoming so inexpensive a good analogy might be automobile powered windows. The only cars without them are the cheapest entry models. Scopes are trending that way.

 

You know, a funny thing about people with manual tracking mounts. Their argument shifts like a chameleon. Sometimes, it is how wide-field eyepieces are essential for planetary observing1. Then it morphs in another thread as to how easily they can manually track Jupiter at 1200x with their silky-smooth mounts.

 

Which is it? Since you are a fan of the Pentax 5XO, I think I know the answer wink.gif

 

1 Today a fairly common scope might be 1200mm focal length. And a reasonable magnification for planetary work might be 200x, nearing common atmospheric seeing limits. A 6mm eyepiece would deliver that performance. A 6mm Supermonocentric (SMC) eyepiece has a field stop approximately 54% of focal length (by TMB design). The true field of a 6mm SMC in this example would be 9.28 arc minutes. The ecliptic is centered on the celestial equator, so on average, 900 arc minutes of drift per hour is experienced.

 

Math question: How many seconds of drift time does the 6mm SMC offer in a 1200mm scope?



#459 Jeff Morgan

Jeff Morgan

    Hubble

  • *****
  • Posts: 13,996
  • Joined: 28 Sep 2003
  • Loc: Prescott, AZ

Posted 14 January 2022 - 11:23 PM

Hi Jeff - I figure as time passes, light pollution increases, and I get too creaky to feel like lugging the scope to a dark(er) site, option 2 might be my preferred choice.  Can night vision devices be used with existing eyepieces (e.g. on one side of the diagonal, or with a binoviewer)?  If so, would the scatter associated with multi-lens, wide-field eyepieces get amplified, accentuating the difference between them and minimal glass eyepieces?

 

I get that the field is limited by the NV device, but if I already had the eyepieces, would there be an advantage to trading them for minimal glass?

 

When a NV eyepiece is used, it can either be Prime (the device is the eyepiece), or Afocal. In the afocal configuration the NV eyepiece peers into a regular eyepiece.

 

When afocal is used, it is typically with a long focal length Plossl. 

 

However, backing up two steps - scatter is really only a consideration in planetary and double star observing (and then only really tight doubles). NV really is not a player in these realms.

 

And is DSO astronomy, scatter does not matter, it really applies to small scale detail.


  • Sarkikos and davidgmd like this

#460 turtle86

turtle86

    Mr. Coffee

  • *****
  • Posts: 6,462
  • Joined: 09 Oct 2006
  • Loc: L2

Posted 14 January 2022 - 11:59 PM

The ZAO I's, of which 400 sets were made (but way fewer of the optional 34 mm), 100 sets sold in the US, took over a year to sell out at about $260 each, but that was before the online hype about them. The IIs took a while as well, despite the online hype about ZAOs.

 

The last regular run of the SMs took forever to sell out. Markus priced them at what he called "fire sale price" of about $115 IIRC and some focal lengths still took over a year to sell out. Markus blamed that on the review in S&T that found astigmatism in the eyepieces, said the sales immediately dropped to zero. Tom Back blamed it on saturation of a very small niche market in which 3000 of the eyepieces were sold. When Markus did small runs after that he required down payments before manufacturing because of his experience doing another run of the TMB 100 f8 refractor. He was besieged with requests to do another run of this superb scope, but once he did that turned out to be a lot of hot air and it took a long time to sell that batch.

 

Tiny eyepieces, with short eye relief and small fov, that give a small improvement in contrast under excellent seeing in scopes with excellent optics is a small fraction of an already very small market. I like the ZAOs, but I bought the Is when they were originally offered, so they were a screaming deal. I tried the SMs but the combination of small fov and very strong field curvature, given my age and my eyes' lack of ability to accommodate, resulted in a tiny soda straw fov, not my taste.

 

The Supermonos didn't work for me either for the same reasons.  Plus, most of my scopes are on the fast side, especially my Dobs.  I will say that in my 18", the blue in the Blue Snowball really did seem a little more vivid in the 5mm Supermono I briefly owned.


  • Paul G and Sarkikos like this

#461 RichA

RichA

    Fly Me to the Moon

  • *****
  • Posts: 5,474
  • Joined: 03 Jun 2010
  • Loc: Toronto, Canada

Posted 15 January 2022 - 12:24 AM

I totally agree.  I don’t consider the XOs tight at all.

"Tight" might a term used to describe anyone wearing glasses while using short eye-relief eyepieces but honestly, if someone is using eyeglasses with high-grade eyepieces and the eyeglasses are just there to correct near or far-sightedness, they may as well not use high-grade eyepieces at all.


  • turtle86 and SandyHouTex like this

#462 STEEL

STEEL

    Messenger

  • -----
  • Posts: 477
  • Joined: 24 Jan 2007
  • Loc: Italy (Genova)

Posted 15 January 2022 - 04:11 AM

As much as I like using the 6 and 10mm ZAO II's, I don't miss the 4mm ZAO II at all.

I suspect I would like the 4mm TOE much better.



The ZAO II 4mm is very affected by the superficial impurity on the lens (pupil side), caused by eyelashes and tearing. I have a bad experience observing Mars, luckily I had SuperMonocentric. When I cleaned it well the quality of the ZAO 4mm was back in line with the rest of the set.

 

However, I recommend keeping the 6 mm clean too (it's not difficult, but you have to be delicate). Do not clean them in the open air even if the cloth is perfectly clean. When cleaning, arm yourself with a watchmaker's lens and luminous spotlight. For those who buy them used, check that there are no scratches, because if the dust degrades the image (they are sensitive to this), I have the feeling that the small groove of a scratch does not do less than the dust and could impact on the rendering of the image. However from experience, the maximum yield of 6mm and 4mm occurs only when they are perfectly clean (lens on the pupil side).


Edited by STEEL, 15 January 2022 - 06:37 AM.

  • Paul G, SteveC, turtle86 and 1 other like this

#463 davidgmd

davidgmd

    Viking 1

  • -----
  • Posts: 626
  • Joined: 24 Dec 2020
  • Loc: Maryland

Posted 15 January 2022 - 08:50 AM

When a NV eyepiece is used, it can either be Prime (the device is the eyepiece), or Afocal. In the afocal configuration the NV eyepiece peers into a regular eyepiece.

 

When afocal is used, it is typically with a long focal length Plossl. 

 

However, backing up two steps - scatter is really only a consideration in planetary and double star observing (and then only really tight doubles). NV really is not a player in these realms.

 

And is DSO astronomy, scatter does not matter, it really applies to small scale detail.

 

smile.gif 

Thank you! Looks like I need to spend a little time in the NV forum for some education.

 



#464 Sarkikos

Sarkikos

    ISS

  • *****
  • Posts: 34,444
  • Joined: 18 Dec 2007
  • Loc: Right Coast of the Chesapeake Bay

Posted 15 January 2022 - 10:08 AM

Hmmm.

 

Yes. If you like star hopping, that's great. But compared to DSC's, it is like tapping out Morse Code compared to using a keyboard. And that is probably a generous comparison.

 

A well made (that is to say orthogonal) mount can be equipped with encoders. Manual. Motorized. Doesn't matter. Drive systems are becoming so inexpensive a good analogy might be automobile powered windows. The only cars without them are the cheapest entry models. Scopes are trending that way.

 

You know, a funny thing about people with manual tracking mounts. Their argument shifts like a chameleon. Sometimes, it is how wide-field eyepieces are essential for planetary observing1. Then it morphs in another thread as to how easily they can manually track Jupiter at 1200x with their silky-smooth mounts.

 

Which is it? Since you are a fan of the Pentax 5XO, I think I know the answer wink.gif

 

1 Today a fairly common scope might be 1200mm focal length. And a reasonable magnification for planetary work might be 200x, nearing common atmospheric seeing limits. A 6mm eyepiece would deliver that performance. A 6mm Supermonocentric (SMC) eyepiece has a field stop approximately 54% of focal length (by TMB design). The true field of a 6mm SMC in this example would be 9.28 arc minutes. The ecliptic is centered on the celestial equator, so on average, 900 arc minutes of drift per hour is experienced.

 

Math question: How many seconds of drift time does the 6mm SMC offer in a 1200mm scope?

I don't think I've ever said any x is essential for any y.  I try not to deal in absolutes and essences.  Next we'll be discussing Aristotelean substances.  wink.gif

 

I try to speak from my own experience and sometimes from the reported experience of others - especially when their experience agrees with mine.  lol.gif

 

My experience says that the XO's - and to a slightly less degree the HR's - show a sharper, more contrasty image with less scatter than eyepieces like the Ethos or even the XW's. 

 

But my experience also says that it takes less work to nudge a non-tracking mount when an Ethos or XW is in the focuser.  Sometimes I want sharper.  Sometimes I want easier.  But overall I'm too lazy to deal with the additional weight and complexity of a tracking mount, especially for a heavier OTA like a 10" f/4.7 Newt.  The older I become, the less I want weight and complexity.  Maybe the future will bring a lighter, easier tracking mount that is not a toy for folks who like to futz around with gizmos.  Maybe not.

 

I've never owned a SuperMonoCentric and probably never will, for all the usual reasons.  Many observers share this opinion.  Even to bring up an SMC is pretty much a red herring.

 

About star hopping.  For those with experience star hopping, and who know (I mean remember) the constellations, the bright stars and the locations of many DSO, star hopping is enjoyable and easy.  And easy.  Star hopping with SkySafari Pro on my iPhone is very enjoyable and very easy.  When I purchased my DM-6, it included DSCs.  But the DSCs were an impulse buy.  I've never used them.  I've never felt the need to use them.  It really is irrational to buy something you don't need and won't use.  I try to be a rational consumer, though I don't always succeed.  When I bought the DSCs, I was not being rational.  grin.gif

 

I don't want to keyboard in the dark at my telescope, although I am a fast touch typist.  I tried a lap-top at the telescope about ten years ago and didn't like it.  I prefer a small tablet, or even better a smartphone.  I played around with learning Morse Code when I was 12 years old, like most 12-year-old boys.  (Do they still do this?)  No analogy is perfect - or it would be an identity - but this one is flawed. 

 

Mike


Edited by Sarkikos, 15 January 2022 - 10:34 AM.

  • turtle86, Astrojensen, StarDust1 and 2 others like this

#465 Sarkikos

Sarkikos

    ISS

  • *****
  • Posts: 34,444
  • Joined: 18 Dec 2007
  • Loc: Right Coast of the Chesapeake Bay

Posted 15 January 2022 - 10:23 AM

"Tight" might a term used to describe anyone wearing glasses while using short eye-relief eyepieces but honestly, if someone is using eyeglasses with high-grade eyepieces and the eyeglasses are just there to correct near or far-sightedness, they may as well not use high-grade eyepieces at all.

While viewing at the telescope, I keep my eyeglasses on for only two reasons:

 

1) to correct for astigmatism at low power

 

2) to allow me to look at the sky and also read without having to switch my eyeglasses on and off.  This is especially important while star hopping.  I star hop.

 

While viewing at the telescope, I take my eyeglasses off for only two reasons:

 

1) to observe comfortably - and see more of the field - with short eye relief eyepieces

 

2) to try to see a detailed object more sharply (mostly planets and the Moon) or to see a dim object more clearly (very faint galaxies, nebulae and star clusters).  Taking the glasses off does not always make a difference, but it's worth a try.

 

Mike


Edited by Sarkikos, 15 January 2022 - 10:23 AM.

  • turtle86 likes this

#466 payner

payner

    Gemini

  • *****
  • Posts: 3,026
  • Joined: 22 Mar 2007
  • Loc: Bluegrass & SW Appalachian Regions, Kentucky

Posted 15 January 2022 - 11:00 PM

 I tried the SMs but the combination of small fov and very strong field curvature, given my age and my eyes' lack of ability to accommodate, resulted in a tiny soda straw fov, not my taste.

I tired the ZAO II (purchased when in production)) and they did not work well for me. Too limited in focal lengths for planetary use if one wants to dial-in best magnification for seeing in a given aperture. I do not see the issue with field curvature in the Supermonocentric eyepieces and use them in telescopes with focal ratios of 7 to 10.


  • SteveC and j.gardavsky like this

#467 Paul G

Paul G

    Cosmos

  • *****
  • Posts: 9,757
  • Joined: 08 May 2003
  • Loc: Freedonia

Posted 16 January 2022 - 08:08 AM

I tired the ZAO II (purchased when in production)) and they did not work well for me. Too limited in focal lengths for planetary use if one wants to dial-in best magnification for seeing in a given aperture. I do not see the issue with field curvature in the Supermonocentric eyepieces and use them in telescopes with focal ratios of 7 to 10.

 

Young enough eyes can accommodate. Yuri of TEC measured field curvature of some planetary eyepieces and the SM had the strongest by a large margin. The chart was in the files section of their old discussion group, not sure if it transferred to the new.


  • Sarkikos and SandyHouTex like this

#468 Sarkikos

Sarkikos

    ISS

  • *****
  • Posts: 34,444
  • Joined: 18 Dec 2007
  • Loc: Right Coast of the Chesapeake Bay

Posted 16 January 2022 - 08:16 AM

Young enough eyes can accommodate. Yuri of TEC measured field curvature of some planetary eyepieces and the SM had the strongest by a large margin. The chart was in the files section of their old discussion group, not sure if it transferred to the new.

Yet another good reason for me not to acquire Supermonocentrics. My eyes no longer accommodate well - or at all? - for focus. 

 

I can immediately tell if a system shows field curvature.  I no longer use Baader Zooms unless they are Barlowed or in an f/10 or slower scope.  I also put a field flattener on fast refractors.  The SM's would not be a good match for me.

 

Mike


  • SandyHouTex and oldphysics like this

#469 payner

payner

    Gemini

  • *****
  • Posts: 3,026
  • Joined: 22 Mar 2007
  • Loc: Bluegrass & SW Appalachian Regions, Kentucky

Posted 16 January 2022 - 10:19 AM

Mike: If you get the opportunity to try the SM you may be pleased. One thing I've learned is everyone's accommodation, value of certain optical characteristics/qualities, telescopes used, etc, is different and make a "one size fits all" or "mine is better than yours" approach to not be generically applicable. It is similar to eye relief, just read through all these threads on how this tolerance varies almost to an individual. I've read few people mention FC as a distraction to observing objects these specialized eyepieces are intended in their use.


  • Paul G and Sarkikos like this

#470 SteveC

SteveC

    Voyager 1

  • *****
  • Posts: 11,345
  • Joined: 15 Jun 2006
  • Loc: Sunshine State & Ocean State

Posted 16 January 2022 - 10:44 AM

I found the 4mm ZAO II uncomfortable myself, pretty much on a par with the 5mm XO, and only used it a couple of times.  

For a few months, I owned both ZAO I's & 2's. Like most who have owned both sets, I could not perceive any differences using my TEC140. I did not compare the 4mm's in both sets(just the 6, 10, 16mm's) since I hardly use that f/l with the TEC140. 

 

I did some comparisons using the 4mm ZAO II, the 4mm & 5mm Supermonos, and 5.1mm XO on Jupiter using the TEC110 over 2 consecutive nights. I was less impressed with 4mm ZAO II's sharpness and contrast when compared to the others. I was very impressed with the 5.1mm XO, since it overcame the my bias towards Supermonos. It was equal in all respects to the 4mm and 5mm Supermonos. I have never observed with the 2.5 XO.

 

I own the 25mm ZAO and it is a sweetheart..........how's that for a subjective evaluation(I haven't compare it to any other eyepieces). Years ago I tried to pick up the 34mm, but I was always late responding. I have no interest at this point because of the price and since I would hardly use it.

 

Edit, I eventually sold the ZAO I's, but kept the 25mm.


  • turtle86, Sarkikos, SandyHouTex and 1 other like this

#471 Jeff Morgan

Jeff Morgan

    Hubble

  • *****
  • Posts: 13,996
  • Joined: 28 Sep 2003
  • Loc: Prescott, AZ

Posted 16 January 2022 - 10:45 AM

Young enough eyes can accommodate. Yuri of TEC measured field curvature of some planetary eyepieces and the SM had the strongest by a large margin. The chart was in the files section of their old discussion group, not sure if it transferred to the new.

http://www.astrosurf...ent/tectest.pdf

They also had zero astigmatism. Astigmatism can not be removed by the tweak of a focuser knob.

 

If your mount tracks, fc is no problem at all. It can be focused out anywhere in the fov. 


  • SandyHouTex likes this

#472 turtle86

turtle86

    Mr. Coffee

  • *****
  • Posts: 6,462
  • Joined: 09 Oct 2006
  • Loc: L2

Posted 16 January 2022 - 11:22 AM

For a few months, I owned both ZAO I's & 2's. Like most who have owned both sets, I could not perceive any differences using my TEC140. I did not compare the 4mm's in both sets(just the 6, 10, 16mm's) since I hardly use that f/l with the TEC140. 

 

I did some comparisons using the 4mm ZAO II, the 4mm & 5mm Supermonos, and 5.1mm XO on Jupiter using the TEC110 over 2 consecutive nights. I was less impressed with 4mm ZAO II's sharpness and contrast when compared to the others. I was very impressed with the 5.1mm XO, since it overcame the my bias towards Supermonos. It was equal in all respects to the 4mm and 5mm Supermonos. I have never observed with the 2.5 XO.

 

I own the 25mm ZAO and it is a sweetheart..........how's that for a subjective evaluation(I haven't compare it to any other eyepieces). Years ago I tried to pick up the 34mm, but I was always late responding. I have no interest at this point because of the price and since I would hardly use it.

 

Edit, I eventually sold the ZAO I's, but kept the 25mm.

 

I had the 25mm ZAO I for a while too.  It's a gem and sometimes I wish I had kept it.  Over the years I've had a couple of chances to buy the 34mm ZAO I, but never had any serious interest as my scopes are too fast for it and the asking price was well out of my range.  Those who got them at the original price got a great deal.



#473 csrlice12

csrlice12

    ISS

  • *****
  • Posts: 30,536
  • Joined: 22 May 2012
  • Loc: Denver, CO

Posted 16 January 2022 - 11:53 AM

I have never observed with the 2.5 XO.

 

You should......In the right conditions, it's better than the 5.1XO....as a plus, it has a few tenth's of a mm longer eye relief.....you also get a free eye floater checkup.


  • turtle86, Sarkikos and SandyHouTex like this

#474 SteveC

SteveC

    Voyager 1

  • *****
  • Posts: 11,345
  • Joined: 15 Jun 2006
  • Loc: Sunshine State & Ocean State

Posted 16 January 2022 - 11:53 AM

I tired the ZAO II (purchased when in production)) and they did not work well for me. Too limited in focal lengths for planetary use if one wants to dial-in best magnification for seeing in a given aperture. I do not see the issue with field curvature in the Supermonocentric eyepieces and use them in telescopes with focal ratios of 7 to 10.

I also like to dial in magnification, so I have the Supermonos to fill the gaps between the ZAO II's. I have all the SM f/ls including four pairs for binoviewing. Consequently, I sometimes ask myself if I really do need to keep the ZAO's, but I kept and use them, nevertheless, along side the SM's - because I can. Diversity is a good thing, and besides, the expense was written off a long time ago. 


  • turtle86, Sarkikos and shaesavage like this

#475 SteveC

SteveC

    Voyager 1

  • *****
  • Posts: 11,345
  • Joined: 15 Jun 2006
  • Loc: Sunshine State & Ocean State

Posted 16 January 2022 - 12:10 PM

You should......In the right conditions, it's better than the 5.1XO....as a plus, it has a few tenth's of a mm longer eye relief.....you also get a free eye floater checkup.

lol.gif  Trust me, the floater checkup I get with the 2.9mm ball is good enough for me. I suspect that I would use the 2.5mm XO  as rarely as i use the 2.9mm ball. Perhaps someday I'll run into someone with a 2.5mm at a star party and get a chance to evaluate it.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics