Changes

# * Acquire a ..... ~11th mag star (e.g. one of the spectrophotometric standards) with the guide mirror in the beam* Position the star on the appropriate red box on the acquisition image* On the instrument schematic, set the guide mirror to Science (so that light reaches the slit)* Also insert the rear-of-slit mirror into the beam to direct the light to the Lodestar (rear-of-slit) camera* View the stand-alone rear-of-slit software window * Click on the "continuous" button for an ongoing series of 2 second exposures* Open the slit wide, to about 4"* Adjust the slider bars at the bottom of the image (both most of the way to the left) to set the brightness and contrast* Use the hand-paddle to position the star near the centre of the slit (in both X and Y)* 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* Best focus is where the star is as round and sharp as possible