20 inch f8 Chief Ed Jones designed and a 17 f9 Zanbuto Wide Band Chief Mike Jones designed .Both unobstructed telescopes .
A 60mm department store refractor started it all....
Quote:Thanks for posting. I hadn't realized just how good that design can be. How wide a field does the 0.5inch spot represent?dan
Quote:What I've seen so far tells me that for both elements, radii should be held to 0.1% either side of nominal, thicknesses should be within ±0.005", and element wedge should be less than 0.001".
Quote:s Kevin will almost exclusively use this as a visual instrument, there wasn't a need to design for a field wider than 1" diameter. It could be done, but at the expense of sharpness over the central 1" format. I have experimented with wider FOV's using a third element, but so far I have encountered diminishing returns
Ed Jones ........... The best data is an interferogram, the best analysis is from an honest optician.
Quote:Mikes design is very good.Maybe better than anything in 17 inch .All for two little lens and a fancy holders .Thanks for the work.
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.