ATM Re: >Can someone tell me where focus for any given eyepiece is located.

[Chris Westlnad <westland@uxmail.ust.hk>]

I've been curious about this also ... is there a source that summarizes
the location of the focal plane for various commercially available
eyepieces?



> >Can someone tell me where focus for any given eyepiece is located.
> >Is it before the lens, middle of the lens, or after the lens?
> 
> Depends on the type of eyepiece. Some designs. like the Naglers, have
> the focus between the elements, others, like Orthos, Erfles, Plossls or
> Kellners have the focus in front of the elements. The focus is usually defined
> by a circular baffle (field stop) which defines the edge and apparent
> size of the field.
>




Chris Westland
Associate Professor, Hong Kong University of Science & Technology
Clearwater Bay, Kowloon, HONG KONG  
Tel: ++(852) 2358-7643  Fax: ++(852) 2358-2421
EM:westland@uxmail.ust.hk  WWW:http://home.ust.hk/~westland/westland.htm