In reference to Ed Turner's recent warning about the possibility of some time being pre-empted so that we can get regular Shack-Hartmann checks of collimation, I thought everyone would like to know of one silver lining: any instrument may be run at the same time as the Shack-Hartmann. This means that while the S-H observations are being made by the observing specialist, you make take biases with DIS or SPIcam, darks with GRIM, or any cals using the internal lamps on the Echelle or Fabry-Perot. You will not have control of the telescope, nor can we allow the lamps on the truss to be turned on, but hopefully you won't find the time a complete loss. The observing specialist will also work with the observers to find a time window for the pre-emption that's least disruptive to the science being done, within the constraints of the S-H requirements. I'll also add that the results we've obtained from the September observations (kindly donated by Ed himself from his PU04 program, with some other contributions of time from Chris Stubbs) indicate that there is indeed a problem of changing collimation, and we have hopes that diagnosing it will enable us to improve image quality significantly. Russet McMillan. APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 615 in the apo35-general archive. You can find APO the archive on http://www.astro.princeton.edu/APO/apo35-general/INDEX.html APO To join/leave the list, send mail to apo35-request@astro.princeton.edu APO To post a message, mail it to apo35-general@astro.princeton.edu APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO