For electric focuser usage go here

Focus will need to be checked throughout a session as it could change because of one or more of the following factors:

·         Thin cloud over target.

·         Changing atmospheric conditions.

·         Change in temperature affecting optics/telescope tube.

·         Mechanical slack.

Watch HFR graph on NINA to decide when focusing is needed.

HFR/FWHM/Bahtinov Mask methods

Focusing

Bahtinov MaskGenerator – Google Drive