In /home/user/bin on the workstation computer you will find a focus script called "cosfocus". This is a basic focus script, other scripts modified by recent observers mimic the LFC focus script. Take a look at these scripts, make new onesas you desire. Please do not delete any pre exisiting scripts.
It is suggested to use 0.2 mm steps to get a rough focus, 0.1 mm steps in good seeing, and 0.05 mm steps only in the very best seeing.
The spacing between the first and second exposures is twice as big as between the remainder of your focus exposures.
Approximate focus for COSMIC in the reimaged mode is 22.0 mm for the r filter. Approximate focus for COSMIC in the direct mode is 21.0 mm for the r filter. Other filters (and filterless) foci relevant to the r filter are given here for the standard filters.