"So not talking something at the level of a ZAO or XO in its execution,"
The eyepiece you hanker for has already been invented and produced. The only criteria you mentioned that would not be met is price. Why not reissue ZAO's and XO's? There are always some who will pay for the best possible quality apart from price. I have read dozens of CN reports comparing Explorer Scientific eyepieces to TeleVue and other premimum offerings. It always comes out that if the issue is best value for the money, then ES wins. ES eyepieces in general might be a tad less performers than Televue and other premimum eyepieces, but why not save a hundred or more dollars per item and go with ES? Yet, people will pay the extra for slightly better performance. If the price point to reissue ZAO's or XO's would be thousands more per item, then most would not pay. However, reservations could be taken and eyepieces built for as many as subscribed.
Don't want a ZAO-level eyepiece. Or a overly complex overly scatter burdened one either. Just a good quality classic design like an Abbe, 1-2 Konig, or Symmetrical that is available in 1/2mm increments from 3.5mm to at least 8mm (if just satisfying the Apo market and some of the production Dob market - i.e., tailored for scopes with 800mm to 1300mm focal lengths). So that is the parameters as they evolved in this thread from the original posting. No one has made anything like that.
Would not want to do this with ZAOs or XOs because at those production cost levels 10 eyepieces would cost what? $5,000! No thank you. Now something on the level of a Tak Abbe which come in around $150 would be much more doable. Or something of the quality of a TV Plossl which comes in around $100 for the mid-range focal lengths. So 10 of those would be $1,000 which is much more manageable for something that is not available from anyone else.
But actually, I can beat this by integrating some Barlows to bring down the number of eyepieces needed. So if we say what we want is to only make 6 eyepieces, all in the longer focal lengths as these have better eye relief than trying to use a 3.5mm Plossl as example. And integrating the Barlows will mean the ER will be pushed out to more comfort still. So if you make these little potentially $100 quality Plossls in 12, 14, 16, 18, 20, and 22mm, then also make 2 Barlows for the set in 4x and 2x, then from those 6 focal lengths you will get 18 focal lengths that are 2mm apart in the bottom third, 1mm apart in the middle third, and 1/2mm apart in the top third giving smooth magnification increases of many times just 20x to 40x jumps for scopes with focal lengths of 800mm all the way up to 3600mm (i.e., a C14)! So if those special eyepieces with their classic even Symmetrical design come in at $100 each (that would be a TV-level pricing, so $600, then say $150 for each Barlow for $300 total, then we again have this Planetary package for $1,000 and it can service every scope from a 4" Apo to a 14" SCT with a smooth range of small magnification increments from 150x all the way up to a 0.4mm exit pupil and smaller! Yes not ZAO performance, but as good and probably better than TV Plossl or Tak Abbe performance since the parameters are not for these to operate at f/5 and go out to 50 degrees but instead f/6.3 and 45 degrees so the on-axis can be optimized more (and even better if a 1-2 Konig is used instead sine this has the best on-axis spots of the three designs).
So that is my take. Then we have lylver's take where he wants the Barlow element internal to each eyepiece so would be making 3.5mm to 8 or 9mm in 1/2mm increments or 10-12 eyepieces. That concept does not need separate Barlows but again if the build and optic quality is similar to a TV Plossl would imagine these could come in for another $50 since the Barlow is integrated so let's say $150 each. More expensive at $1500-1800 but then no Barlow to manage.
Finally we have Thomas who came up with the out of the box suggestion to just make a constant AFOV zoom over a much larger focal length range, maybe 3mm to 30mm, using the Zeiss concept called a Pancratic Zoom which they have already fielded in the microscope world! That would be mind-blowing!!
Anyway, nothing out there today does this with a view quality (crispness and contrast) on par with say a Tak Abbe Ortho or even a TV Plossl (which no wide field offering is up to for planetary) and small sub 1mm focal length increments over the 3.5 to 8mm or 9mm range.
PS - the inspiration for this multi-Barlow aproach came from a private PM discussion with CNer RFeaster.
Edited by BillP, 01 June 2020 - 09:50 PM.