Fair enough. Maybe I've never really noticed it because I always go paracorr on wider field EP's. The only time I don't is if I'm doing planetary work, when it's all about the center of the field anyway, and atmospheric dispersion plays a bigger role, to my mind.
Part of me feels like I should try harder to see if I can detect it in my scopes, but then I think what am I doing? I'm happy now. Why mess with happy? Why re-ignite that eternal lust for the perfect eyepiece? I guess it's all part of becoming a better observer, becoming more aware of the good and bad.
Cheers
Markus
Quote:
Originally Posted by ausastronomer
Hi Markus,
I've owned all of the 1.25" Pentax XW's for about 20 years. The 14mm and 20mm both show field curvature in my 3 Newtonians. 18"/F4.5, 14"/F4.5 and 10"/F5.3. They show slightly less field curvature in the 10"/F5.3 than they do in the F4.5 scopes. While I can see it in the 10"/F5.3 the eyepiece is still very useable and performs very well. I find them still very useable in the F4.5 scopes as well, notwithstanding there is a bit more FC. They actually have less field curvature and astigmatism than the 17mm and 22mm Nagler T4's in all of my scopes when no paracorr is used.
Use a paracorr in any of the scopes and the field curvature completely disappears in the Pentax XW's and the Nagler T4's and they perform superbly. No idea what they do in refractors. I use those as finderscopes 
Cheers
John B |