Hi Ed,
Thanks for the reply.
I haven’t noticed an issue as such, but don’t seem to get as sharp a view as others have described with similar scopes, or the same level of magnification without it starting to blur. To date I’ve assumed / hoped that was just due to poorer seeing conditions.
However, I made my first attempt at collimating the scope recently, as a star test had showed it to be slightly out. When I tried to turn one of the collimation screws the whole secondary moved very slightly sideways. It did move easily back to it’s original position and upon further examination I noticed that the secondary holder locking ring wasn’t fully tightened, so nipped it back up tight.
This did then make me wonder whether the secondary had been off centre to start with and maybe that was why I’m not getting sharp views, hence why I wanted to check it’s position, or indeed whether it being exactly central mattered. Previous star tests did show the scope to be in rough collimation at least.
I wasn’t sure if measuring to the tube edge would be sufficient as that assumes that the primary is also mounted dead centre. I know the corrector plate is shimmed to align it with the primary.
I was able to complete the collimation just before the clouds came over and haven’t had a clear night since to check things out on a familiar target.
Tim