Re: ATM (no subject)

["Richard Keppler" <rkeppler@telusplanet.net>]

On Tue, 10 Jun 1997 21:49:20 -0400, Gary Myers wrote:

>Richard Keppler wrote:
>  Shim the focusser until you can see
>> that the laser dot does not move when the focusser is racked to and
>> from either extreme.
>
>This is not, I am sorry to say, a good means of checking the focus axis.
>It is however a good means of checking the "runout" (correct mechanical
>term) in the focuser and another problem with truly obtaining
>collimation with all eyepieces!.

 You are entirely correct.  Thank you for pointing out this erroneous
statement.  It is also possible to check flexure over the focusser
range, with suitable weights strung from the focusser, but it cannot
determine the squareness of the focusser on the tube.

Rick.