Jump to content

sgl_imaging_challenge_2021_2.thumb.jpg.72789c04780d7659f5b63ea05534a956.jpg

Modern wide field vs ortho eyepieces


Recommended Posts

I would like to canvas opinions regarding the relative merits of these two classes of ocular. I am fully aware of the fashion for ever widening field of view of modern multi element eyepieces, but ultimately most widefields seem to fall over when combined with relatively fast scopes (f/5 or so). The only major gain that I can see is that with manual tracking they hold the object being viewed in the field for longer. Given that the narrower field orthos generally are sharper and more contrasty than all but the most expensive wide fields, would any ortho user consider it a worthwhile trade-off? It would be interesting to hear any views. Are there any dedicated ortho users who can persuade me to ditch my 80 + degree eyepieces and opt for a "better" view albeit with a smaller field of view.

Link to post
Share on other sites

Some targets just look great in a wide field eyepiece, where as narrower fields just don't frame it right at the same magnification. A good number of years ago now, I was observing the planets with a friend but only had my 20mm Pentax XW with me as a wide field eyepiece. My friend offered me the use of a five element Meade 4000 26mm super plossl. I was a bit insulted as I was a Pentax snob and had an aversion to anything Meade. I reluctantly put the 26mm into my FC100DC  and was stunned by the instant clarity. Also, the 52° field was essentially the same real field visually as my 20mm 70° Pentax, and as sharp if not sharper towards the edge. Also, the five element super plossl, a pseudo masuyama design, was sharper on axis than the Pentax. Today I have only one wide angle eyepiece and its an 85° 16mm five element Masuyama, which is not great at the edge, but is impressively transparent on dso's. With the exception of my Vixen High Resolution set of eyepieces, my single 16mm 85° Masuyama and a pair of 16.8mm orthoscopics, all my other eyepieces are 52° pseudo Masuyama pairs, from 35mm down to 5mm. I love their sharp, transparent orthoscopic view and their lightweight design. And if I need to examine a large extended object, I move my scope a fraction rather than have the discomfort of rolling my eye to examine a field that's too large for natural human vision.

  • Like 1
Link to post
Share on other sites
42 minutes ago, mikeDnight said:

. I was a bit insulted as I was a Pentax snob and had an aversion to anything Meade. 

You a brand snob, Mike? You’ll be telling us how much you like Takahashi next.

 

🤣

  • Haha 1
Link to post
Share on other sites
24 minutes ago, azrabella said:

Interesting reply. I'd not really considered the quality (super) plossl, but I guess I'll have to look to the TeleView series.

Televue's are nice in the longer focal lengths, and that's probably an important point. I use a binoviewer with a barlow for lunar and planetary observing, so there's good eye relief with 25mm to 10mm. The 18mm is my most used focal length. For star fields and nebulae the 35 to 20 are beautiful, though the mental block of 50° might plague some. Plus I don't wear glasses for observing, so long eye relief isn't essential for me.   I think if I were to return to wider field eyepieces I'd go for the Baader Morpheus range, and perhaps a 30mm XW or 31mm Nagler as my lowest power.

It might also be worth remembering that just because the word Super may appear on a plossl, it doesn't necessarily make it a "super" plossl.

Edited by mikeDnight
Link to post
Share on other sites

For me, it's the super short eye relief of orthoscopics at short focal lengths that really bugs me.  I have enough astigmatism that taking my eyeglasses off even at a 1mm exit pupil causes a noticeable drop in resolution for me.  As such, I stick with my Pentax XLs, XWs, and Delos.  I know I'm giving up a bit relative to TMB monocentrics, ZAOs, TAK TOEs and Vixen HRs, but I'm willing to live with it for comfort sake.  During the latest Mars opposition, I found much better resolution to be had with my entry level Arcturus binoviewers and 50 year old B&L microscope wide field eyepieces than with my best monovision wide field eyepieces.

At lower powers, it's simply no contest.  My 25mm Edscorp Abbe Ortho is simply no match for a 22mm Nagler T4 or 30mm APM UFF in edge to edge sharpness at f/6, especially when you figure in the vast difference in field sizes.

Edited by Louis D
  • Like 1
Link to post
Share on other sites

I really like my Circle-T Orthos. The image is so clean. I have a driven scope so the small FOV isn't a problem.

I've started using them exclusively on planets and the moon. I find with the moon the small FOV allows me to concentrate more on individual features and not get distracted by the expanse.

Of course, there's nothing better for doubles.

  • Like 1
Link to post
Share on other sites

If you are on a budget, the best performance per £ spent will come from an ortho I think. The Baader Classic orthos offer amazing performance for their <£50 cost IMHO.

If you can splash out, there are wide angle eyepieces that get very, very close to ortho performance such as the Tele Vue DeLite's and Delos and the Pentax XW's.  These also the observing comforts of long eye relief, a large eye lens and a wider apparent field.

 

 

 

 

Link to post
Share on other sites

Since the OP didn't really specify cost, I took the topic's debate to be between wide field and narrow field eyepieces in general.  At the high end, narrow field eyepieces like the ZAOs, TMB monos, TAK TOEs, and Vixen HRs still outperform their similarly or lower priced wide field competitors.

  • Like 1
Link to post
Share on other sites
10 hours ago, azrabella said:

I would like to canvas opinions regarding the relative merits of these two classes of ocular. I am fully aware of the fashion for ever widening field of view of modern multi element eyepieces, but ultimately most widefields seem to fall over when combined with relatively fast scopes (f/5 or so). The only major gain that I can see is that with manual tracking they hold the object being viewed in the field for longer. Given that the narrower field orthos generally are sharper and more contrasty than all but the most expensive wide fields, would any ortho user consider it a worthwhile trade-off? It would be interesting to hear any views. Are there any dedicated ortho users who can persuade me to ditch my 80 + degree eyepieces and opt for a "better" view albeit with a smaller field of view.

I have Nagler, XW, ES 92 deg, Delos, and LVW EPs and none fell down in fast scopes (at least down to F/4.1). Only the MaxVision 24 mm 68 deg fell down at that F ratio, but it is fine at F/6, and is claimed to work well at F/5. Only a first class ortho could perhaps better the views in a Pentax XW, but at the expense of FOV and eye viewing comfort. My widest EP is the ES 12mm 92 and it is superb. I used to have two orthos: a 25 mm Ioved, and a 5 mm I hated. A key problem with the classic Abbe ortho is that it is a scaled design, and that therefore the eye relief is a fixed fraction of the focal length. The views at the short end, with your eyeballs practically gleud to the lens are very uncomfortable, especially with glasses. The same holds for Plössls, or any scaled design. Moving to long eye relief EPs has just improved the comfort of viewing dramatically, and the reduction of strain means it is much easier to pick out fine detail.

In theory, picking out faint detail should be better with a reduction of the amount of glass, and in particular the number of the air-glass interfaces. However, having the image bounce up and down because your glasses nudged the EP yet again rather offsets the subtle advantages that might be obtained.

Just my tuppence. I still have one ortho (25mm for solar H-alpha, and with 20 mm eye relief)

  • Like 1
Link to post
Share on other sites

I’m not sure it’s helpful to frame the debate this way - but it is your question and I know what you’re getting at.  I have a pretty eclectic bunch of eyepieces including a 13mm Ethos, 8 and 10mm Delos, 5 and 7mm Pentax XW and pairs of the Tak orthos at 6, 9 and 12.5mm to use mono or bino. The wider fields are all ‘sharp’ with, to my eye, the 10mm Delos being marginally the sharpest and most transparent, followed by the 8mm, and the other three differ more in character than in quality. The orthos are perhaps a teeny bit sharper than the best of the ‘wide fields’.  But here’s the thing, I think, the modern wide fields - at least the ones I’ve mentioned - are all so good that in actual use sharpness and contrast do not present as issues. I know the Ethos maybe isn’t quite as sharp as the Tak orthos and I know the Pentaxes show colour in a way the orthos don’t but the differences are inconsequential when set against the other experiences these excellent eyepieces offer. And it is about options, I think. You can take in M42 with a longish Ethos or dig into the Trapezium with a shortish ortho. Both are valid and distinctive observing experiences. There is a lot to be said for doing both at a session because, even allowing for differences in spec, eyepieces often give surprisingly different renditions. I found a world of difference, for example, in the presentation of Mars last year when viewed through the 2 Pentaxes, the 6mm Tak ortho and a 6.5mm Morpheus. Some would say you can have the best of both worlds with, for example, the short focal length Ethoses.  In the interests of debate, if I had to choose from the eyepieces I know one range to stick with, it would be the Delos. But I’d rather be allowed to keep a varied and versatile toolkit. And incidentally, I think that might involve resisting the psychological pull towards building complete sets of any one model or range.

  • Like 2
Link to post
Share on other sites

For an introduction to affordable high quality eyepieces, you can't beat orthos. If you want to push your observations to the limits on faint objects then orthos are the way to go. I did some comparisons of my 5mm Baader Genuine Ortho vs my 5mm Pentax XW. The BGO had a very small edge in contrast but felt much harder work to use with the small FOV and short eye relief. The result is that the XW is my first choice in most cases. However, if I'm struggling to pick something out then the orthos come out. That's why there's a 9mm BGO that sits next to the 10mm Delos. 

  • Like 1
Link to post
Share on other sites
22 hours ago, Louis D said:

Since the OP didn't really specify cost, I took the topic's debate to be between wide field and narrow field eyepieces in general.  At the high end, narrow field eyepieces like the ZAOs, TMB monos, TAK TOEs, and Vixen HRs still outperform their similarly or lower priced wide field competitors.

Though people vote with their wallets.

Three of the 4 eyepieces you mention are discontinued and only available used.  And every time new eyepieces get added to my Buyer's Guide, they seem to be widefields.

You can download the Buyer's guide here:

https://www.cloudynights.com/topic/758306-2021-eyepieces-buyers-guide/

  • Like 1
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.