Quote:
Originally Posted by GrampianStars
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There 1209 can be remotely controlled. While it doesn't allow you to predict a given focus setting as it does not know its absolute position, nor does it offer automatic temperature compensation, it does have the ability to reach focus using software auto-focus routines. It still has significant advantages over focusing by hand.
Additionally, the 1209 is a Crayford style focuser, which virtually eliminates backlash. It has a relatively short travel distance (I recall around 15mm), meaning you can set the primary mirror focus position, lock it, and have enough play to maintain focus throughout an evening; however if you want to switch to a terrestrial target, you will need to refocus by first unlocking the primary and then do the rest by hand.
Microfocusers with absolute value readings and temperature compensation will be of little use to someone outside of an observatory setting, as they need the primary to be locked down and then calibration run. If you move your primary, the calibration values will be useless.
Regards,
Eric