This is a reply to Kris Stanek: The shutter is not set up to time images longer than 720 seconds. To do so, you will have to either time it manually, or rely on the Unix "sleep" command to time for you. The latter can be inaccurate if the machine gets heavily loaded. How innaccurate is not known to me. So, I made a routine that should work, but it is a low level command: ############################################################################# # Long Stares Operation # ############################################################################# # exposures longer than 720 seconds # must be done with a less accurate timer, # namely the Unix sleep command. # a recipe for a 900 second exposure follows: fnstar-OAC> sxt 900 # set exposure time to 900 fnstar-OAC> cc beginSleepReadout # take exposure # and to take a dark frame: fnstar-OAC> cc beginSleepReadout 0 # take dark, 900 sec exposure ############################################################################# that is cut and pasted from the primer from a new version of DOP that I cut. Instead of "setup dop", do a "setup dop devel" and you will be able to use "beginSleepReadout". It will find its way into the real dop in a few weeks. jim APO APO APO APO APO Apache Point Observatory 3.5m APO APO APO APO APO This is message 20 in the apo35-dsc archive. You can find APO the archive on http://astro.princeton.edu:82/apo35-dsc/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-dsc@astro.princeton.edu APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO APO