ok, there is one last remaining thing I'm not sure about re collimation and I'm hoping someone can give the answer I so desperately need.. anyway,
I have now gone thru collimation from scratch at least 3 times, this involves the following:
1.carefully centering the secondary using a sight-tube with colored paper opposite the focuser and white paper blocking tube so I just see the face of the secondary and nothing else, by sliding the sight tube down so the secondary fills the tube FOV I can get it perfectly round and perfectly centered.
2. removng the paper and tilting the secondary so the primary mirror appears centered (and I can see all 3 clips etc) and the center-spot is centered under the sight tube crosshairs (this is quite hard since the crosshairs are very fuzzy and out of focus) I then use the laser to get the spot dead center in the center marking.
3. Using the cheshire now, tilt the primary to line up the cheshire reflection with the center mark. finally double check with laser and lo and behold! it seems to agree..
BUT..
every time I do this the reflection of the spider is not quite centered on the primary center-spot.
so my question is, should it be? Given that everything else seems right why is this always slightly out in one axis (no more than a 1-2 mm, the triangle center-spot is "touching" the spider reflection it just doesn't pass thru dead center)
