Delos V's Baader Classic Ortho V's ZAO-II @ 10mm

[alan potts]

I remember a fair bit before Christmas members were talking about XO and other things, at the time Tele Services still had the 5mm and I thought about getting it, the 2.5mm is just too short, they still have one of them. Anyway by the time I thought yes they had sold it. They were for sale at 335 euros which going by what you say is not bad, it's the same as a Delos pricewise.

Alan.

[alan potts]

John,

Why feel guilty you are only like me we want the best of both worlds. The 18mm I have gone for is a Kasai so that may well be a new one to site. I wanted an Orthoscopic for the LX so give it every chance with the Pup later in the year.

These eyepieces we have are very tempting and we know the only way to deal with temptation is to yeild to it. Oscar Wilde I believe. How right he was.

I don't know if you will get back to read this post but have you tried the Powermate with the BGO Orthos.

Alan

[michael.h.f.wilkinson]

I am not too surprised by the outcome of the test. An Abbe orthoscopic design has just 4 glass-air interfaces, and a very short path through glass. Both effects increase internal transmission to the max. The key factor then is simply the level of the coating (and the quality of the glass to a much lesser extent). My MgF₂-coated circle-T orthos of the past were good, but I bet the XWs beat them (certainly for eye relief). Zeiss (where coatings were invented) will have put the top of the line coatings on their 4 glass-air interfaces. Pentax and TV will have coatings of similar quality but on a larger number of surfaces, thus reducing transmission (by a gnat's whisker). The BGO will have good coatings, but not quite as good as the Zeiss, most likely. The BCO may be a very slight step down from that level again.

Having said all that, I am absolutely sure I see more through an XW, than through a Zeiss Abbe orthoscopic, simply because I cannot get to the exit pupil of the latter.

Incidentally, the Pentax XO is a very different design from the Zeiss Abbe orthoscopic. Orthoscopic refers to lack of distortion, essential for astrometry in the past, not to a particular design (the TMB Paragon was an orthoscopic 68 deg EP)

[E621Keith]

Just saw the shorter focal length TMB supermono are back. APM has 5,6,7,8,9,10,12 and 14mm listed on its website, selling for €470 each !!!

http://www.apm-teles...350&next_page=2

...

Incidentally, the Pentax XO is a very different design from the Zeiss Abbe orthoscopic. Orthoscopic refers to lack of distortion, essential for astrometry in the past, not to a particular design (the TMB Paragon was an orthoscopic 68 deg EP)

Indeed. The XOs are 5 and 6 elements barlowed plossl. However, Pentax used best of everything in the XO and it is said to be as good as the ZAO II by those who have used both. The Smyth lens increases the ER and the 5XO feels more comfortable to use than a 5 BGO by a small margin. Both ortho have more ER and more comfortable than a 6mm Vixen NPL, but both feels like torture when compare to the 5 LVW.

While Pentax said they use Pentax SMC coating on, XL, XF, XW, and XO, I think they use different grades of coating for each. My XL zoom doesn't come close to my XO when it comes to controlling flare and scatter on planets despite both have 6 elements. The zoom was also beaten by the 8 element LVW or even the 12 element Nikon HW*. Modern anti reflection coatings has got to a stage where the number of elements is less critical than the quality of the glass and coating on each.

*(the HW also beat every non-ortho I owned on stray lights and internal reflection, including the 8 elements Nikon SW, which further support the hypothesis that manufacturers put different grades of coating on different line of eyepiece)

[alan potts]

Keith,

I know it is a bit of a dumb question but are the Supermonocentric eyepieces good, I have a feeling John once had one. Are they Orthos or like the XO's. Wonder if they do buy two get one free.

Come to that what are the Takahashi LE's like I don't think I have ever seen anyone mention them before. I was going to get one from Telescope House but they were out of stock at the time.

Alan

[John]

The TMB Supermono's are very good indeed - the 5mm I had was just a tad better on the best nights than a 5mm University HD ortho (which is the same quality as the Baader GO 5mm). The original TMB Supermonocentrics had a limited production run I think so are rather rare. APM in Germany have arranged for a new production run of them but the price has risen to 395 Euros apiece now. I think they still have some stock. The AFoV is around 30 degrees with eye relief similar to Baader GO's. The eye lens of the 5mm was tiny ! - even smaller than a 5mm BGO.

I was happy to let mine go in the end as I found the Pentax XW got very close in performance terms with so much more comfort

If you want the ultimate Alan, seek out the Zeiss ZAO I or II's. They are the yard stick that everybody uses when discussing the ultimate eyepiece of this type.

[E621Keith]

The TMB mono, ZAO, and XO are often rated as the best planetary eyepieces by people on CN. Pentax 0.965" SMC ortho, XP, Brandons, and CZJ ortho are grouped into the second tier. I have only used the XO so I don't know how the others compare.

3 elements monocentric have the least number of air glass interface (2 in mono vs 4 in Abbe). In the days before anti-reflection coatings, it'd be most resistance to internal reflections. Monocentrics have very narrow FOV (30deg).

I think the Takahashi LE were modified Masuyama with a Takahashi stamp and a higher price tag. I haven't heard much about them either, but I think people on CN rate them similar to TVP and put it in the third or fourth tier.

Edit: need to type faster next time

[E621Keith]

...

APM in Germany have arranged for a new production run of them but the price has risen to 395 Euros apiece now. I think they still have some stock.

...

€395 is the export price (ex VAT). They are €470 in Europe (inc 19% German VAT)

[John]

€395 is the export price (ex VAT). They are €470 in Europe (inc 19% German VAT)

The original TMB Supermonocentrics were £200. I paid £100 for the 5mm I had and sold it for the same. Perhaps I should have held onto it and cashed in !

[alan potts]

I may well keep an eye open for one of the Zeiss goodies, when ever I see them they always seem to be for sale from Spain which worries me a little. I guess one could be Ethos expensive.

Alan.

[Astro_Baby]

Well the reason they arent made is pretty much as Keith has suggested but I think critically people saw them as dinosaur eyepieces and people are swayed to wider fields. Newbies taking their cue from glossy ads want a huge chunk of glass with a big field. When you compare a BGO which is a piddling little thing with a tiny eye lens and then look at what else you can but for £75 ( when they were £75 ) like a whopping great big Skywatcher Panaview or a huge chunk of glass like an ES heart rules head and the big glitzy eyepiece with its wide fields will win.

Orthos were hardly mentioned on any boards, at least as far as I can recall, a few years ago. I dont reall too many people waxing lyrical about BGOs or VTs, oh sure tyere was a lot of ooohing and ahhing over ZAOs, Monos occasionally but very litte on the more bread and butter orthos.

I am as guilty as anyone for falling for, maybe even helping to, perpetuate the hype of widefields. For myself ai was put off orthos by a bad experience. Merlin on here told me to stop whining and buy some orthos about three years ago. It was excellent advice which I completely ignored for a year. Inbought some on the advice of talitha, who used to post here, in the end and found them excellent. Hearing rumours of their demise I quickly emptied the piggybank and bought a near complete set of Circle Ts and a load of BGOs just in case.

It will be interesting to see if once the Kasais are available there is a take up. My own gut feel is that tere wont be enough volume for Kasai to keep making them, the market by and large wants ever wider field of views and the numbe of people who want just a good high contrast eyepiece and are prepared to put upmwith short eye relief to get it jsut wont be enough. That would be very sad. It would be a tragedy if orthos were to go foreever and deprive a new generation of their magic.

Whats sad as well is that in an age of cheap GoTo and tracking mounts, which can maximise the orthos narrow field they should die out. In an age ago the narrow field was always a headache when tracking mounts were expensive and rare. Now we have availability of mount technolgy undreamed of even 10 years ago, tracking accuracy which allows an ortho to shine and yet it seems we could lose this class of eyepiece. I will be hoping that we dont.

Some sage wiser than I commented that beginners want maximum power, the amateur wants widest possible field but the real afficianda wants contrast above everything.

[John]

.....Some sage wiser than I commented that beginners want maximum power, the amateur wants widest possible field but the real afficianda wants contrast above everything.

Thats a good one

[Stargazer_00]

Going to get a bco next week. Never tried any ortho and these seem a reasonable punt. Not far off the others if expect especially to my eye.

[Damo636]

Apparantly Agena are shipping the new Hutech orthos from tomorrow.....

http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/5805175/page/0/view/collapsed/sb/5/o/all/fpart/1#Post5805255

[Stargazer_00]

they look fugly to me

[michael.h.f.wilkinson]

..............

Some sage wiser than I commented that beginners want maximum power, the amateur wants widest possible field but the real afficianda wants contrast above everything.

I would qualify that a bit. First of all, it depends upon the object, and the observing task. If I am looking for faint fuzzies, throughput, or transmission is the key, contrast is secondary (though the two often correlate). On planetary viewing contrast is much more important than transmission. For measurement, we need lack of distortion. The classical Abbe orthoscopic design combined these properties very well, even though it will show some residual spherical aberration, especially in very fast scopes. For very fast scopes, designs that add glass and/or aspherical surfaces can improve contrast (but possibly at the expense of transmission). Note however that transmission is perhaps as important as many people think. Even a 5% loss in total transmission translates to only a 0.055 magnitude loss, and 1% loss equates to 0.011 magnitudes. Only in borderline cases might this make a difference. One has to ask whether spending a small fortune on EPs makes more sense than spending that same fortune in getting a bigger scope.

The Abbe orthoscopic EP has two key drawbacks however: small eye relief and small FOV. The latter is not too much of a problem, except when viewing wide-field objects (the Veil, Markarian's Chain, M33, M31, or any large group of galaxies), the former is. Poor eye relief means poor viewing comfort, and poor viewing comfort means you do not relax as much at the EP, and that often means you see less. You need time at the EP to catch the more elusive details.This is why an observing chair is much more important than going from 98.0 to 98.5% transmission. Especially for us who need to wear glasses, the orthoscopic design (and anything that is based on the original design of Jesse Ramsden (Plossls, Kelners, etc)), is dismal at focal lengths shorter than about 18-20mm (I did have an ortho I loved in my old 6" newt: a 25mm Circle-T. Great little (0.965") EP which I sold with that scope, silly me).

Another point is that getting a wider field EP for your scope does allow you to see large objects better, and need not hinder transmission and contrast much. So whereas you could counter poorer transmission by getting a bigger scope, the same cannot really be said about wide-field EPs.

I also have another problem with EP tests. They are by necessity not "blind." The tester knows which EP he is looking through, and you need to be brave to state that a ZAO performed no better than an XW (let alone a BCO), even if that is honestly what you see. Even if you state you could not see the difference, people will doubt your ability to distinguish the subtle differences that should be there. A test by an experienced observer (or any observer for that matter) is valuable, but when differences become very small, it is hardly an exact science. The order in which we do the comparison will affect the outcome. Suppose we look at a borderline visible object, one that slowly becomes visible in averted vision. At first you have difficulty finding it in the first EP you try. You then switch EPs and find it easier to spot, because the brain has worked out where to look. Guess which one is likely get the better rating, unless you switch back and forth between EPs, try multiple objects with the EPs in different orders. Many good testers do this of course.

I have seen comparisons of scopes on planets, with claims that a 4" triplet APO shows more detail than a quality 8" reflector or SCT. Simple physics tells you that that can only be true if the observer did not take sufficient time at the EP. This can be verified by comparing images taken through the scopes, which is trickier with EPs.

Again, I know that in many and probably most cases people doing the tests are doing their best to give an objective assessment of the eyepieces they are testing. The point is that it is very difficult to get right. I am just saying that when it comes to small differences, it is very difficult to be precise, and you must always wonder how important these subtle differences are compared to the fickle nature of the atmosphere, or simply the time you take looking through the EP instead of at it.

Having said all this, it would be a pity if orthos disappear, but I think there will always be a manufacturer who knows there are people out there who want to use them

[John]

It looks like the Hutech Ortho's will be shipping in the USA from 19th April so, for those who value the design, hopefully we will have another option available in the UK in the near future.

Having 2 good orthoscopic ranges available will be a lot better than none

[Qualia]

Excellent write-up, Michael and a great insight into various EP types and the manner in which comparisons may already come 'loaded' no matter how hard the reviewer tries to remain 'objective'.

Although I have never tested various quality EPs and may have this completely wrong, I get the impressionn that a quality Ortho will give great contrast and sharpness, for example, but lack eye-comfort and FOV. A quality Plossl like a TVP will try to offer a little wider field of view but as its focal-length decreases eye-relief may in fact become even more tighter. Naglers may drop a smidgen on the former features of Orthos' sharpness and contrast, for example, but will make up for this with a massive 82º FOV and a little better eye-relief. Pentax XWs or a Delos will offer a very wide but narrower field of view but come with extremely comforting eye-relief and according to many sources, a quality of contrast and deepness comparable to our proverbial Ortho. Radians will have the same eye-relief but only 60º AFOV and may in some examples drop a smidge on contrast and light transmission. The Ethos offer a huge 100º FOV, have similar contrast and transmission to a Delos but will drop a little on eye-relief, and so on.

Again, I may have this all wrong, but I get the impression that although there are differences the similarities are greater and where premium does differ is more a matter of emphasis.

[michael.h.f.wilkinson]

Excellent write-up, Michael and a great insight into various EP types and the manner in which comparisons may already come 'loaded' no matter how hard the reviewer tries to remain 'objective'.

Although I have never tested various quality EPs and may have this completely wrong, I get the impressionn that a quality Ortho will give great contrast and sharpness, for example, but lack eye-comfort and FOV. A quality Plossl like a TVP will try to offer a little wider field of view but as its focal-length decreases eye-relief may in fact become even more tighter. Naglers may drop a smidgen on the former features of Orthos' sharpness and contrast, for example, but will make up for this with a massive 82º FOV and a little better eye-relief. Pentax XWs or a Delos will offer a very wide but narrower field of view but come with extremely comforting eye-relief and according to many sources, a quality of contrast and deepness comparable to our proverbial Ortho. Radians will have the same eye-relief but only 60º AFOV and may in some examples drop a smidge on contrast and light transmission. The Ethos offer a huge 100º FOV, have similar contrast and transmission to a Delos but will drop a little on eye-relief, and so on.

Again, I may have this all wrong, but I get the impression that although there are differences the similarities are greater and where premium does differ is more a matter of emphasis.

That's about right. The Nagler T4s have good eye relief, but some say there is a very slight drop in contrast compared to T5 and T6 Naglers. I have not noticed any clear difference between my 31T5 and 22T4 and 17T4 (difficult comparison with such different exit pupils). In Olly's 20" Dob, I could not spot clear differences between his 26T5 and my 22T4. The difference in transmission between a Radian and an XF or XW was quite striking, and in particular the colour neutrality of the XF and XWs was better.

[John]

When I'm comparing eyepieces for optical performance I find I need to use targets which really challenge the conditions, scope and observer, to reveal differences between them. I also find that you need to compare eyepieces directly with their peers, keeping the conditions, scope and targets consistent, and over a number of sessions to quantify their differences. Doing it from memory just doesn't really work !

The above probably reflects how eyepiece quality generally has moved forward today so most eyepieces give fine views of commonly viewed targets, particularly in the central part of the field of view.

I have a few orthos which I'll use on certain objects where their characteristics give them a slight edge but much of the time I'll use my wide and ultra wide eyepieces.

But I'm lucky to be able to run some duplication of eyepiece focal lengths. Most folks will want to maintain just one eyepiece set for all purposes.

[Stargazer_00]

One thing I've found very important across the board in this hobby is comfort. Comfort is incredibly valuable and worth paying a bit extra for. I know that's a very general statement but I feel it applies right across the board in this hobby, regardless of what specifically you are buying you should always ensure that comfort in use is considered. If it isn't comfortable to use you wont use it (in my experience).

[John]

One thing I've found very important across the board in this hobby is comfort. Comfort is incredibly valuable and worth paying a bit extra for. I know that's a very general statement but I feel it applies right across the board in this hobby, regardless of what specifically you are buying you should always ensure that comfort in use is considered. If it isn't comfortable to use you wont use it (in my experience).

Thats a very good point. I went right off using orthos for just this reason. I do use them from time to time now though because there are just a few occasions when I've found that they can show something that more complex (and comfortable) eyepieces can't, or at least can't do so well on.

[E621Keith]

When I'm comparing eyepieces for optical performance I find I need to use targets which really challenge the conditions, scope and observer, to reveal differences between them. I also find that you need to compare eyepieces directly with their peers, keeping the conditions, scope and targets consistent, and over a number of sessions to quantify their differences. Doing it from memory just doesn't really work !

The above probably reflects how eyepiece quality generally has moved forward today so most eyepieces give fine views of commonly viewed targets, particularly in the central part of the field of view.

I have a few orthos which I'll use on certain objects where their characteristics give them a slight edge but much of the time I'll use my wide and ultra wide eyepieces.

But I'm lucky to be able to run some duplication of eyepiece focal lengths. Most folks will want to maintain just one eyepiece set for all purposes.

Indeed. Changing eyepiece make a small difference to the final image. Changing scope make a big difference. Changing seeing condition or observing location make a VERY BIG difference.

For DSO observation my 3" APO with a zoom in a clear night at a dark site will crush my C925 with exotic eyepiece in my garden in an average night.

In reality, in 90% of nights my orthos do not show any more details than my LVW. Only in a few very steady and clear nights would the ortho show more than other eyepiece.

Eyepiece comparison needs to be carried out side by side over many observing nights on the same scope.

[alan potts]

Everyone,

I was just going to rate this thread as a 4 star thread as there is some really good content from members and I accidentally gave it only one star. Sorry to one and all.

Alan

[alan potts]

Keith,

I guess to get the best from these top draw Orthos you need to using them in a scope of similar quaity and with the seeing as good as it comes. I am still kicking myself for missing out on the XO 5mm, this thread has reminded me of it again. Still it is my own fault people like you and some of the others that have posted on this thread broadcast enough warning of them being withdrawn.

Alan.