Astigmatism - why a problem?

Astigmatism is something I have, and I view generally without glasses. I can notice the astigmatism in my 13mm EP and anyhting with a longer focal length.

However, in order to find that astigmatism is present, I have to de-focus the image. Now like most astronomers, I actually view the sky while the image is in-focus.

So what deterioration to a focused image does astigmatism cause?

Gary Weber

Hi Gary --

I have astigmatism too and notice what look like defocussed stars in parts of scope views which correspond (I assume) to the worst areas of astigmatism. Wearing my glasses corrects the problem.
This is just me. It's my guess that everyone's astigmatism will affect viewing differently.
Prior to a year ago I always viewed without glasses but since then the image quality problem has been obvious which may mean that age also has something to do with it.
If your astigmatism isn't a problem, enjoy!

Bob Polcyn