jetstream

Ok youve hit a weak spot! I really want one of these... right up there with the ZAOII's

This diag points out why I was separating the true Plossl from the achromat pair... we can see what happens to the colors and spot size as we veer off axis. This really does show why I like orthos- excuse me I better be specific- Abbe ortho lol! as we all know that orthoscopic is not a design but a condition Even the beloved very narrow monocentric suffers "bigly" off axis. I'll take an Abbe any day. Never heard of the H orthos being around- true ones.

Vg idea Alan, but after a couple of years of trying to find out-nothing. I just threw it out there on the off chance someone might know as related to Baader COO. Not sure if many know but Baader bought out Zeiss's inventory and design info when Zeiss left the astro world. This is how it was explained to me. No big deal really.

When I was seriously looking at these many said the 9mm was the best of the whole line up. Not to insinuate the rest are poor.

What I'm very interested in is where that superb 95mm APO by Baader is made- rumours in the coffee shop say is bests the Astro Physics... and others. anybody know? ps when I asked Baader they wouldn't reveal where the optics came from...

German optics have a deserved reputation for excellence. Insinuating a German connection is purely a marketing ploy IMHO.

Like I said- I do see on axis differences in sharpness and the Delos is right up there in this department, bested by the Zeiss zoom and Docter by a bit under the best of conditions. You were right btw- years ago a discussion led to the idea that the Zeiss zoom loses a bit of sharpness right near the high end of its range, barlowed or not- and I see this. The Delos is the deepest widefield out there and I've been comparing the Doc to it in this regard and its very close, but the nod might be going to the Delos. I test scatter in the TSA120 and Zeiss prism diag. Televue has a very good build on all the Delos I've tried- my 17E is on the chopping block due to the super 17.3mm. With regard to complex lens eyepieces- not only does the design matter but possibly more important is the execution of the design and the quality control so there no "good ones" but all of equal and top quality. My 7mm KK is top tier, my 5mm KK sub par... Eventhough I don't own "top" orthos, I've sorted through a bunch to come up with good ones and use these on the faintest of galaxies and PNs with great luck. The vg 25mm TV "plossl" is my goto Horsehead eyepiece was the first to show it in my 10" dob. My pair of 32mm TV plossls are a fixture in the Binotron 27s for low power lunar viewing in the 15". So maybe I won't use the 10mm MA after all (worst EP Ive ever had) and keep on going with the TV's, Doc/Zeiss and the superb Vixen HRs- and of course my beloved cheap orthos.

This is fantastic news! I only observe on axis and as such will just use the 10mm Ma and not my 10mm Delos as the on axis difference will be comparatively small.

Yes I'm feeling very very blue right now I just new I should have stuck with the 10mm MA supplied with the H130! What a blunder - I bought other eyepieces...

Back a couple of years ago I checked all my newts for this, including the H130. For the H130 I used a simple 1.25" Celestron cheshire/sightube combo strapped with weights simulating eyepieces. I checked for weight "height" also simulating taller eyepieces. It is amazing how well these scopes work when used with appropriate eyepieces. I'm wondering if the H150 can take a bit more EP weight than the H130- are the truss tubes the same diameter and length? Btw, checking my 15" dob revealed that past 1/2 travel on the Moonlight would de collimate (focuser flex) using binoviewers and on the VX10 the tube would flex and de collimate. Actually very hvy eyepieces in conjunction with the needed focuser extension would aggravate this. I really like your videos Chris and look forward to watching more

I would be interested in your findings if you test the effect of eyepiece weight on the collimation of the H150.

Sadly it seems as if I have wasted a lot of money on eyepieces when I guess theres not much difference between them. Apparently no need to keep buying new ones. Good to know.

It is my experience that excellent seeing shows up the differences in eyepieces more than anything else. It is under these conditions that I rate my eyepieces and there are differences in on axis sharpness between some of the "top" contenders. Obviously vg optics are needed for a discriminating test and ones that are in good collimation. After noticing differences in the 15" dob, I checked all again in the TSA120 which is as close to a perfect optic I'll ever own and the differences remain. Is it possible that those who don't see the differences don;t have the eyes to see them? Don, do you see differences in sharpness between the Nagler 3-6 zoom vs the Vixen 3.4mm HR?

Personally I find the Docs AMD minor but again maybe its the interaction of the eyepieces design AMD and my eye/brain. No I don't see the moon getting "squashed" lol! Years ago I tested every eyepiece I own for distortion- wrote it all down, comparisons etc, it was enlightening but I threw the list out and now just enjoy my shortlisted eyepieces. BTW, there is more pincushion in many EPs than there is AMD in the Doc- to my eyes. Interestingly enough there are a few sets of eyes that report the same.

Lunar, hands down binoviewing. Planets are vg in binos too but under my best seeing the bino optical train limits my mag to about 435x whereas mono goes 700x+. This is with my 15" dob.

"28 - Fukumoto 100° eyepiece (the 1st of 5 examples in the patent application) is a basis of the Nikon NAV-HW ultrawide (7/10 arrangement). There is obvious similarity in the general configuration with the Ethos, but it is also a design with its own characteristics, such as more complex Smyth lens, and near non-existent spherical aberration of exit pupil. 29, 30 - Another Fukumoto-Nikon design from the same time frame is 82° AFOV design with a very complex Smyth lens and relatively simple positive counterpart. Five of the six examples in the patent application do not feature the front two singlets; most have similar edge performance as the one shown here, but somewhat more astigmatism in the inner field. Reduction in the overall size is very obvious. Subsequent 2015 Fukumoto-Nikon patent expands the field of this eyepiece type to 100°. Patented version shown (the preferred one, out of five) shows very good correction up to 45°, or so, and the astigmatism flare up toward field edge doesn't show on the astigmatism graph in the patent application. Since a small change in one of the radii (R8, box to the right) nearly brings it to where it should be, there is probably a typo in the patent prescription. 31 - Design based on the published configuration for APM "Ultraflat" 84° eyepiece (originally 12.5mm f.l.) with no other data. It also turned out to be a viable configuration, with a very good correction over the entire, flat field, and long eye relief."

What Holger seems to indicate in his research is that distortion IS viewer dependent eventhough the distortion in the optic is obviously a "fixed" amount for each eyepiece design. I personally see less distortion in the Docter (in the form of barrel distortion)- than in eyepieces with an abundance of pincushion ie Ethos. Yes I can see 2 close stars get a bit closer near the edge of the Docter but I like this much better than having the moon "egg out" in my Ethos at the edge. I see no "rolling ball" or golbe effect in the Docter. The Docter is an extremely "sharp" eyepiece, with high transmission (to my eyes). Question: did APM clone the Docter 12.5mm UWA somewhat with their 12.5mm 84 deg? https://www.apm-telescopes.de/en/eyepieces/more-74-ultra-wide-angle/apm-lunt-eyepieces/apm-high-eyerelief-flat-wide-84-degree-12.5-mm-eyepiece.html "31 - Design based on the published configuration for APM "Ultraflat" 84° eyepiece (originally 12.5mm f.l.) with no other data. It also turned out to be a viable configuration, with a very good correction over the entire, flat field, and long eye relief"

There is info out there to help with picking which distortion and how much of it you can live with. I dislike a lot of pincushion distortion for some viewing and this may explain my choices. I tend to shy away from pincushion for all except widefield nebula viewing. http://www.holgermerlitz.de/globe/test_distortion.html http://www.holgermerlitz.de/globe/distortion.html ^^ "This indicates that the amount of distortion generated by the human vision might differ from individual to individual. " An example:

The Docter shows less distortion than some of my Abbe orthos....and much less than most TV's- at least to my eyes and the TV's I've tried. It might be my eyes and the type of distortion.

Agreed, my 12.5mm Docter UWA is an orthoscopic eyepiece.

Anyway, the spot diagrams show why I like orthos. The TV "plossls" are well executed but still limited by their design, like all others.

Well, maybe asymmetric doublet pairs? It seems as if it might be a symmetric achromatic pair with different outer lens curves.

Does this design show its a pair of symmetric doublets?

Is the Televue Plossl a plossl? Some say it is a simple symmetric... From Lord: "I have also provided a historical perspective to the designs of the König, Brandon and TV Plössl, and reasons why, despite TeleVue’s advertising claims, the TV Plössl is only a Symmetrical, and consequently incapable of a noticeably superior performance. I have been made aware of the reputation of Plössl eyepieces in general and the TV Plössl in particular. My findings leave no doubt that the reputation is unwarranted. When it comes to the detection of low contrast detail and preservation of low contrast details in planetary images (Jupiter in this instance - a difficult object owing to its low surface contrast) there is nothing about the TV Plössl design to commend its preferred status to either the Zeiss Abbe Orthoscopic or Zeiss König I, or the Brandon Orthoscopic." https://www.brayebrookobservatory.org/BrayObsWebSite/HOMEPAGE/BRAYOBS PUBLICATIONS.html