Quote:
Originally Posted by casstony
The XW14 and 20 curvature doesn't work well with many scopes producing fuzzy outer fields.
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That is indeed a common complaint about the XW14 & 20. I had the 14mm and used it with fast Dobs and indeed there is visible FC for me. But it's pure FC and can be refocussed for sharp-to-edge stars. Some people have eyes with better "auto-focus" and are more tolerant to it.
I found the XWs 10mm and under faultless. Also the 30mm 2", which is unfortunately no longer available. I find the edge performance of most Naglers not that great in Dobs f/4.5 to f/6. And it's not just FC but aberrations that cannot be got rid of by refocussing. A coma corrector will fix that but the XW10,7,5,30 don't need a coma corrector in the same scopes to produce nice round sharp stars to the edge of field.
I'm not a Nagler fan at all. (I've owned T4s and T6s and spent plenty of time with T5s at star parties.) But I am impressed with the Ethos. That is like the XW (except 100 vs 70 degree FOV!) ito of how it works very well in fast scopes (f/5) even without coma corrector: sharp to edge, unlike Naglers (for my eyes).
Eyepiece choices are very subjective. We all have a different imperfect lens inside our eyeballs that we have to live with. My best guess is that people who say that Naglers are tack sharp to the edge of field have better eyes than mine.
I've never tried a Delos.