Re: ATM Eyepiece Focus

[andydtg@alpha1.phoenix.net]

Re:

>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.



Andy Saulietis / DTG Alt-Az-Fp Drive Systems
12617 Harriet Ln
Santa Fe, TX 77510 USA
409-925-8854 Voice/Fax