Re: LX200 focusing issue

On Thu, 29 Sep 2005 16:40:29 GMT, "Orion" <Orion@xxxxxxxxxxxxx> wrote:

>Hey all,
>
>I have an LX200, 10". When coarse focusing on Mars the other night I found
>that the image would move across the field of view as it focused in and out.
>It has never done this before. Can anyone give me an idea what's going on?
>Is it a collimation problem perhaps? Thank you!

This is normal behavior, an inevitable result of the design of the
telescope. The amount of movement varies from unit to unit. It happens
because the mirror cell can rock on the baffle tube that carries it. You
may be noticing it more now if you are working at a higher magnification
than usual, or because something has changed. That something could be
that the grease on the baffle has gotten uneven, or it could be that you
are using the scope at cooler temperatures than in the past. Try
redistributing the grease by running the focuser from end to end several
times- that usually makes the movement much less severe.

The focus shift isn't related to collimation, although in cases where
the mirror rocking is severe, collimation can be affected (although this
is rarely significant).

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com
.