Quote:
Originally Posted by mental4astro
I've also had a Nagler 30mm EP with its 80deg FOV in the same scope- also appauling- way too wide and impossible to overcome the astigmatism the EP/stumpie light cone combination creates. I also needed to move my head to see the whole image this EP provides, not just my eyeball- our eyes can see well within a 68degree range, NO coincidence!
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You'll find the Naglers are highly corrected and show no astigmatism. In fact they show beautiful coma that can be corrected by a Paracorr. I say beautiful coma since only a highly corretced eyepiece will show it properly as poorer corrected eyepieces have astigmatism added.
Any astigmatism you may see using the Nagler would be either the eye or mirrors (pri or sec). Often the eye when straining to see the edge of field will show considerable defects from the eye.
The Nagler has a much flatter field than cheaper 80deg clones also giving sharper stars at the edge.