[AG Hybrid (Adrian)]

Originally Posted by Don Pensack

A couple points:
1) The 30mm ES 82 degree DOES have a small amount of vignetting. It's hard to see, though.
2) The 9mm ES 100 is styled after the 8mm Ethos. The 8mm Ethos, if used as a 2" eyepiece, has it's perfect coma correction setting when pulled about 1/2" out a Paracorr. It may be the same with the ES 9. Here is how you would test:
--set the coma corrector for perfect correction on the 14.
--exchange the 14 with the 9mm.
--focus the eyepiece with the top of the coma corrector only--do NOT use the focuser. If you run out of travel, and I'll bet you will, pull the eyepiece out until it is in focus. THAT is the proper setting for the 9mm.
--you may need a 2" barrel extender and a parfocalizing ring to allow you to automatically insert the eyepiece to that point in the future.

Just note that the coma corrector will parfocalize all your eyepieces when it is set correctly. You won't have to touch the focuser knob at all except maybe for the very finest of focusing. I find the actual amount of focuser travel, once the eyepieces are parfocalized by moving the top up and down, is about 1mm tops.

Things I have noted and agree with. The 30mm and 14mm are sensibly parafocal. Only a very slight adjustment is required. Your right about the 30mm with the vignetting. Tiny amount. Its starts at about the outer 10% I would say. The field is improved so much I don't even care about it though.

One problem your hypothesis for the 9mm Don. From the 14mm's position of best focus. The 9mm comes to focus turning the top of the corrector inwards. Not outwards. Or turn top left for in focus and right for out focus.