Focusers and OTA wobble

On Sat, 4 Oct 2003 17:15:35 +0000 (UTC), "Janet"
wrote:

I have a Europa 250 and while I'm generally quite pleased with it one thing
that gets by goat is that whenever I adjust the focus the whole damn tube
shifts and wobbles.

Does anyone know of any gadgets that might be useful to reduce this? I've
heard of zero image-shift focusers but don't know what they are. I also
don't know whether a sturdier mount will make any difference: I use an EQ5.

It is indeed a bit of a pain. I have a Europa 250 and a Vixen apo
refractor. Using them together really brings out the difference in
the quality of the components. However, the Europa is intended to be
a budget scope so I guess it's not fair to be too critical.

I've tried to image with the Europa and the image shift is a
nightmare. Mine is quite old now so I don't know if its the same as
yours but my focusser is a basic rack and pinion affair. A plate on
the 'bottom' of the focusser to a degree controls the stiffness of the
focussing action. If you slightly loosen the four screws that hold
this plate into place it may make the focussing action easier. Be
careful not to loosen to far and lose the screws.
--
Pete
Homepage at http://www.pbl33.co.uk
CCD/digicam astronomy