Re: ATM Eye astigmatism in low power viewing ?

["Bob May" <bobmay@nethere.com>]

Ah, not realizing the effects of the optical system, are you Martin?
Here's the thing.  If your eyes are astigmatic (it soulnds like yours
aren't) the larger the exit pupil, the more the light hits the edges of the
7mm (standard by definition of measuring a lot of eyes when fully dialated
by the dark) eye and that is where the astigmatism comes from, more than in
the center of the eye's lens.
Now, this is different than the astigmatism from the optical train of the
telescope where the various surfaces of the telescope and eyepiece can cause
the optical error.  This will be seen by all observers to the same degree as
it is from the optics external to the eye.  On a Newt., the astigmatism will
be done by the eyepiece.  I'll note that some designs are noted for having
that problem to a large degree and I have seen some EPs that the problem is
quite apparent.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net