|
Thanks for the replies, the secondary seems to be pretty much centred, and the view is approximately like the diagram. Looking at that diagram, within the reflection of the secondary I can see the circular edge of the focusser (facing into the tube) and it is that that is off centre, everything else seems centred as in the diagram. The centre spots are over the top of each other.
I guess, it must be, as Rob suggested, that despite appearing to be centred in the focusser, the secondary must be a little high up the tube. But as everything is lined up, does it matter? If the optical axes are lined up together but a mm or two off the centre of the secondary, will it make much difference? I will try Rob's suggestion with the graph paper next time and check.
I can likewise leave my scope out under the veranda to keep at ambient temp - haven't got up that early yet though, having a 3 month baby and 3 year old twins means every moment of sleep is precious!
Ev
|