Quote:
Originally Posted by brunono2
one of the best eyepieces for planetary viewing on short focal length refractors
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Bruno there's a good reason why - the curvature of the focal plane in refractors (and SCT's) is usually convex towards the eyepiece. In newtonians it's concave. Then there's coma, which fast newtonians have. This makes a huge difference as to how eyepieces perform in different scopes.
There is no such thing as an eyepiece that is excellent in all scopes - for that to be true, all scopes would have to produce effectively no aberrations, which simply isn't the case.
Some eyepieces work as well as they do in fast (f/4) Newtonians because to some extent they have a modest amount of negative coma and a curved field to match. This appears to be the case with the Explore Scientific eyepieces, the TV Naglers, Delos and Ethos.
I've only had one occasion to briefly try a Pentax XW20mm and 10mm, which at the time seemed excellent edge-to-edge but I wasn't looking at them critically. Unfortunately I don't know anyone with a set to allow a bake-off with my LVW set.
My only gripe would be the "safety groove", which IMHO is utterly annoying, as one who has never dropped an eyepiece in 40 years.