Collimation: temperatures

[Herbie]

Quick question should you do your collimation in cool temperatures or it doesn't matter?

[Wavytone]

Depends on the scope. With a Newtonian do it after setting up. With my mak, I wait an hour or so for the scope to settle thermally.

[AEAJR]

I don't think the temperature matters as long as the scope has reached equilibrium with the surroundings.