Re: [ATM] Field stop locations

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

Field stop locations are usually where that silly litttle ring in
the tube is.  Some larger EPs, like some that you have mentioned,
use the end of the tube as the field stop or plain just don't
have one as the field is larger than the tube can handle.
The proper way to do this would be to build a little tester that
you c can place an EP on and then find out where the EP focuses
on a targer in the middle of the field.  Zip the EP up and down
and read off where the focusing knob is to find the relationship
between the seating face and the focus point of the eP.
Bob May

rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net


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