Quote:a 'zero power' achro overcorrected for longitudinal color
Homemade 'scopes 8"f/7,6" f/5", 6"f/4, 4.25" Schiefspiegler,60mm Coronagraph,60mm H-alpha system, 4.25" White-light Solar Newtonian,solar spectroscope, 4" f/12, 4.5" f/16 & 6" f/12 Schupmann Medial refractors, 4" Celestar, 19 Stellafane awards 9 in optics Engineering = Taking what you have and making what you need.
Quote:<snip> Wouldn't it be something if it works as planned??!!M.
Quote:Everything at this point is proprietary
20 inch f8 Chief Ed Jones designed and a 17 f9 Zanbuto Wide Band Chief Mike Jones designed .Both unobstructed telescopes .
Quote:Yes, pardon the error!M.
Quote:DAVIDG, personally if I decided to make a dialyte I'g do with a Mangin mirror rather than an achromatic lens corrector. Using three single elements, all of the same (cheap) BK-7 variety, you can achieve full apochromatic color correction, no lateral color to speak of, flat field, fully anastigmatic performance at just about any focal ratio (from f.3.5 and slower), large field size, closed tube, no aspherics, and the whole telescope mounted on a low gravity, stable mount. Rohr's refractor-type solutions just seem like needlessly expensive exercises in futility. In fact, he removed his home page because the designs are outdated!Mladen
Quote:Yours has a large obstruction and is a reflective system . All is not yet known . I know only good thing come from smart people trying new things .When they fail sometimes that is when most is learned .Nothing like having the real telescope to learn from . Obstruction effects are real but we are use to seeing it in the images . Having a design in OSLO is not like having the real telescope . Mark and John knows what he is doing we should relax we might all learn some.
Quote:Thanks for resurrecting that one, Mladen. I need to ping Dane and see if he ever built it. Shoulda been/will be a sweet scope.Mike
Quote:In spite of all that, the retro has no central obstruction or a tilted mirror, it has been perfected by Peter Wise and is an APO, it is cheaper than most with a very high performance
Ed Jones ........... The best data is an interferogram, the best analysis is from an honest optician.
The Jones-Medial is a refractor that has no obstruction, color, coma, field tilt and uses 3 pieces of common glass. I am at the assembly/testing stage on mine although I haven't had much time to work on it the last few months.
Quote:Another Schupmann yet.
Nytecam 51N 0.1W Meade 30cm LX200 astrograph+C8+Ha+CaK PSTs+spectrographs SX M9+Lodestar-C+M CCDs/Canon 1100D DSLR My Meade astrograph-colour deepsky My supernova discovery My dome build/spectroscopes/DSO images/Lodestar colour images & videos
Quote:And by "Joe" he means C2H5O
I am 100% behind exploratory, recreational optical design. It's how I stirred the pot and came up with the designs that Mladen brought up here. Ed Jones and Mark Harry are also recreational explorers, as is Peter Wise and 50-odd other names I could drop. I guess that's why I am offended by the term "tired old designs" above. I could say that this "hypo" thing is also just a recycling of "tired old designs", in this case a Petzval lens, albeit with uncorrected Petval field curvature and lateral color. That's the only "AHA I get it!!" moment I get from a "Hypo". But knowing that doesn't trivialize it or render it undesirable to try building - it's a simple way to achieve a large-aperture refractor while only needing to make but one full-aperture refractive element. That's all Mark has presented this to you as, and I'm looking forward to his First Light report. But can we also respect and welcome other designs as well, and not practice what is effectively optical design racism?