mirror safety.

[loakessg]

Hi.. Might be odd question but... If I'm using my scope on a cold night and collimate it outside adjusting the primary mirror. Can I risk cracking the mirror if I don't loosen the locking screws when I bring it back inside and it warms up again?

[Starlight 1]

The mirror have got room inside the holding clip to move. 

[Peter Drew]

I think there would be no risk of cracking the mirror in those circumstances. The actual collimation screws don't bear on the mirror, the mirror retaining clips (3) should be loose enough to be able to turn the mirror with light finger pressure. 

[loakessg]

Thanks guys

[loakessg]

Doh!!! I had a closer look and the mirror is sitting on a metal ring and the lock\adjusting screws tighten onto the ring. Oh well, must look closer next time!!!

[Geordie mc]

Well, at least we all know now. Better to ask than risk an expensive repair/replacement.

[Rusty-Gunn]

As a newbie it is good to know this. Thanks.