> There is a bit of play on my ST80's focusser tube. I am fairly sure
> that there may have been a shim put in to stabilise it, but probably
the
> glue holding it in place fell out. I have some teflon sheet I could
cut
> and glue in place.
>
> Could someone check their scope to see if there is a shim in the
focusser?

Bruce,

Which brand/model scope do you own?

If its a Synta made model there are three shims that the drawtube
slides on. The lower two that flank the focuser rack are white plastic
and are glued in place. On the top opposing the rack is an adjustable
black plastic glide. You will find two small setscrews that are on
either side of the knurled lock knob. These adjust with a .5mm hex key
to take up the free play.

Does the above describe your scope? If you are missing a shim then
they should be simple to replace and the Teflon would work well. The
only trick is finding something that will stick to the Teflon! I have
often added self stick Teflon tape to the stock glides to improve
focuser motions.

Let us know if your scope is different.

Clear Skies,

Phil Lefever