Bahtinov mask question

[canidae]

Hi all

While we have no clear skies for the foreseeable future I have been looking at increasing my beginner knowledge (and fiddling/making things).

I have seen Bahtinov(hope that is spelled right) masks in various pages and wonder if someone can clarify whether once my camera is focussed through the telescope with one of these will that focus hold for all the stars/planets/moon on view or will the focus only hold for stars and need refocussing seperately for planets and the moon?

Cheers

Dean

[Flea77]

Yep, once focused, it's good to go!

I bought one off the bay that was adjustable and made from hard plastic, I liked that idea over making one because it is very durable and still cheap. It doesn't do any better job, but dew doesn't mess with it either. Something to think about.

[rtlrp12]

Yes, Once focused it will stay for a while, but as your scope and the night air cools, you will need to re-focus. It is also contingent on your focuser holding focus position too.

Stan