To: "Scott Ewart" ,
From: Dennis Rech 
Reply-To: Dennis Rech 


At 03:13 AM 4/15/03 -0400, Scott Ewart wrote:

>|
>| Its best to put a small 1/2" diameter paper hole reinforcement ring on the
>| center of the diagonal and another on the center of the mirror before
>doing
>| the laser pointer alignment trick.
>nter.
>     You WILL get added diffraction with a mark on the secondary.  If you
>really want to use a mark, make it absolutely as small as you can.
>
>Scott Ewart

Thanks Scott,
I probably should have added to peal off the ring after collimation. The
second thing is to calculate the diagonal offset that is required and stick
the center of the ring at the correct offset location if you are really
fussy.
Mostly I just wanted to let people know that the laser pointer works great
only if the eyepiece holder is square with the optical axis of the tube and
the diagonal is properly located on that axis. The broomstick trick and a
small square goes a long way in helping to collimate with a laser pointer.
Dennis

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