Spacehead

To my eye they are straight, I actually twisted one though to see what effect it would have - I couldn't detect any effect so I put it back to how it was.

Hi Andrew, I can state with confidence that yes, the focus tube goes into the mirror reflection - I can see it looking through the pinhole in the collimation cap once the focusser is in beyond a certain point. It is in view at the focus used for the star above. Would not all 200p scopes suffer this problem though if the spike was from that? RE the camera, I have tried two different cameras and the effect is the same - the extra spike is present on both.

Oh the gods - what a mess I made. 6 hours of messing. Got rid of the stretched left side spike - pretty much all the same length now, will have to re-address the extra spike tomorrow as despite a practical complete re-build - its still there. Arcturus and an extra spike

Cheers all - I have just finished resetting everything. Took the primary right back down to base by tightening all the screws - lifted it up again with 2 turns on each - so hopefully perpendicular to the tube. Unscrewed the 3 secondary tighteners/positioning screws and pulled the mount on the mirror right back against the support mount - and then reset from there. Re-collimated. So all being well - I will go out tonight and see what I can do to cause some obstructions and see whats what. Cant see even a fleck of dirt on pri or sec.

Hi All, My Skywatcher 200p is getting on a bit now - and at some point over the last five years it developed these diffraction spike "issues" as in my pic. So there on the left - that spike goes on "forever" whilst the other 3 are the same length. And the top spike is two spikes not one. This is on all photos of bright stars and both problems are really bugging me. Can anyone advise? What can I do to test which spider is wrong (if thats the prob). I collimate it with a cap, the hole is dead center in the donut on the mirror (jfi).