377 | | 1. Monitor focus by checking the image quality on each frame or keeping an eye on the mosstat PSF display. Keep track of the truss temperature variation and use the information to modify the focus as needed. Note that the focus may not respond quickly to changes in temperature, so monitor the images carefully before adjusting focus. The Mayall has astigmatism, so one can sometimes tell from the shape of the images which way to move the focus. Here is a focus correction cheat sheet: |
378 | | |
| 377 | 1. Monitor focus by checking the image quality on each frame or keeping an eye on the mosstat PSF display. Keep track of the truss temperature variation and use the information to modify the focus as needed. Note that the focus may not respond quickly to changes in temperature, so monitor the images carefully before adjusting focus. The Mayall has astigmatism, so one can sometimes tell from the shape of the images which way to move the focus. Here is a focus correction cheat sheet: |
| 378 | [[Image(Focus_Adjustments.png, 512px)]] |