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Old 22-02-2012, 08:39 PM
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cventer
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Join Date: Jul 2005
Location: Melbourne Australia
Posts: 957
Quote:
Originally Posted by mplanet62 View Post
I feel like I've missed something. Autofocus for telescope? Ideal focusing is easy with Bahtinow mask - cheap and effective. If DSLR has live view (even better on computer screen) it's like a toy, too simple. And, with prime focus photography all system needs to be focused once for all session. So what's the point to make simple things complex?
if only it were that simple.

Focus changes on telescope throughout the night as temperature drop and mirrors/lenses stabilise. So depending on scope you need to refocus every 3 - 6 degree temp drop.

Also when imaging not all filters are parfocal so you need to adjust focus for each of your filters.

Automated focus makes this very easy to do and also enables unattened imaging as you can use scripts via automation software to tell your focuser to refocus every hour or if temp drops more than x degrees or when filters are change etc....

if using hand a bhatinov mask however is the ticket

Last edited by cventer; 22-02-2012 at 11:47 PM.
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