Donuts! And er, collimation

[Black Knight]

I've been attempting to align the secondary mirror with the primary on my Quattro for what seems like hours now, but try as I might, I cannot get the laser exactly in the centre of the donut on the primary. The best I can manage is where the laser is just inside the donut circle.

How critical is this alignment? Do I need to get the laser exactly central, or will just inside the circle be good enough?

[John]

With the Quattro being an F/4 I believe you should try and get the collimation as near to spot on as you can. Fast scopes have smaller collimation "sweet spots" than slower ones. Is your collimator in good collimation ?.

[Black Knight]

TBH, I don't know. It's not adjustable.

[Mr Spock]

Try rotating the collimator in the eyepiece holder. You might find there is some variation.

[Black Knight]

Just tried that .... didn't make any real difference unfortunately