[rat156]

Hi All,

What does everyone do about focus shift at this time of year. Today was low-mid 30's here in Melbourne. It's nice and clear tonight, big moon, but OK for some narrowband imaging. The ASA N12 take quite a while to cool down, I have just achieved stable focus at about 2330, which leaves little time for imaging before the sun rises again tomorrow morning.

Other than putting a cooler in my observatory what can I do? I know that Bert has some fancy temperature control stuff on his fast scope, but I'm hoping for something simpler.

I have been focusing between subs, but the focus shifts during 15 or 30 minute exposures enough that I get sub-optimal star shapes.

Cheers
Stuart