Quote:
Originally Posted by electric
The Masuyama line was designed for refractors - that is where the Japanese market is concentrated on.
If you use the Masuyama eyepieces on Newtonians, you will find few perform well edge to edge. Pop them into a refractor, as Col did, and here they excel.
Same for the other Masuyama copies. Great in refractors, and mediocre in Newtonians.
"Fast" vs "Slow" focal ratio has nothing to do with it. What has everything to do with it is matching the shape of the focal plane of the scope with the eyepiece you are using. No use putting an eyepiece designed to work with a convex focal plane in a scope with a concave focal plane.
With the complex nature of contemporary eyepiece design, there will be a couple of the Masuyma line that will perform well in a Newtonian. But that does not mean that the others are crap. They are not. What is crap is expecting an eyepiece designed for a refractor to perform the same in a Newtonian.
Col's experience of this monster new Masuyama is in a refractor, and it performs as expected - brilliantly. Will it perform just as well in a Newtonian - who cares! It may or may not. A Newtonian is not the right scope for this eyepiece. A refractor is.
Electric.
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A good point, though I can't imagine that the f-ratio counts for nothing. For one thing, it will affect the radius of curvature of the focal plain. I also note that people who appear to know far more than I (which is little enough) do specify a minimum usable f-ratio for different eyepieces.
So how do SCTs, Mak, and RCs fit into this picture? Are they curved similar to newts of fracs?