as suggested.
First some further clarification. The newt is a short tube f5 (750mm). The original focuser had a 3" drawtube. The CR2 is only a 2" drawtube, so even though I've put spacers on the crayford to build it up to the same height as the old one, the drawtube isn't as long (but I can use an extension if I need more height). So the 'missing inch' between the old & new drawtube, is the bit that used to protrude into the tube.
If I need to rack out more I've got no problems, since I have an extension tube, however, if I need to rack in the extra inch into the tube (like the old focuser) then I've got problems - since the internal hole is still 1.25". Hope this makes sense. The other issue is - what effect will it have with 2" eyepieces i.e. am I going to vignette because of the smaller hole?
The pics should help to explain. The side view is just the CR2 mounted - to give you some perspective. The front view looks down the drawtube, you will see the edge of the OTA hole at the end. The inside OTA shots show the hole from the other side - in the close-up you can see the slight shadow inside the drawtube.
Hope this helps!
Cheers 4 now....
