Re: ATM Collimation JSO Schmitt Camera

[PFAFF2@delphi.com (Robert C. Pfaff)]

>Hi everyone,
>
>I've been asked by a friend to canvas the ATM forum to see if someone
>out there can help him.
>
>He has a JSO 6 inch Schmitt Camera (400mm f2.5).  The problem is that
>the collimation seems to be out because when he looks at his resulting
>negatives he finds half of the image is blurry, ie. focal plane is
>skewed.
>
>
>Ted

I have never seen a JSO Schmidt camera. So what I say may be useless
 but anyway for a generic  Schmidt read on . If the corrector has no hole in it
you can collimate the the primary by making a temporary dot on the 
corrector plate with a marking pen at the center. In daylite
look for the reflection of the dot on the corrector plate.
When the reflection of the dot  is in the center you are collimated.

Now the film holder must be squared on. You can do trial an error
method. Another way to get in the ball park is place a paper target
in the film holder and use a telescope of equal or larger aperature
to look straight on into the Schmidt. The telescope should be focused
at infinity. Squaring on is very critical in a Schmidt camera as well as
focus.

Bob Pfaff