* Adjust the telescope focus with the hand-paddle in steps of 3-5 units and assess how the star image changes
* The star will move around due to the translation of the secondary mirror, so adjust it back into view with the hand-paddle if necessary
* Astigmatism in the system extends the star image diagonally and the orientation indicates whether the focus is too high or too low: Star extended from upper-left to lower-right: focus number is too high Star extended from lower-left to upper-right: focus number is too low
* Best focus is where the star is as round and sharp as possible
* Optimum focus varies with temperature, typical summer values are ~2200 while cold winter night nights may be closer to 2250 2270 units
===Focusing the acquisition camera===