PNS MANUAL: Taking Science Exposures

How to take on-sky science exposures

The PNS shutter is rather slow, and is controlled from the PNS PC which does not interact with the CCD controllers. This makes for a slightly messy procedure, which involves synchronizing by hand the start of the integrations and the opening of the shutter. The procedure described below uses a few scripts to make this as painless as possible.

Perform the following commands, in sequence:

  1. Once target acquisition is complete, make sure A&G mirror is OUT (check A&G mimic display). If it is not, issue AGMIRROR OUT on A&G console.
  2. Prepare two command lines without hitting return yet (where time is the desired exposure time in seconds):
    1. on DAS prepare expose time "title" - Note (i) that the ""s are necessary if the title contains blank spaces
      (this will start exposures of time+30 and time+70 secs on PNSL and PNSR respectively, to give the shutter time to open and close and to ensure consecutive readouts of the CCDs to avoid crosstalk);
    2. on PNS PC prepare expose time
      (this will open the shutter, count down time secs, close the shutter, and make a horrible noise.
  3. Now hit returns: first on DAS, and once both CCDs have started their integrations also on PNS console.
  4. At the end of the readout, the shutter closes automatically, the PC howls, and the CCDs read out, first PNSL and then PNSR. If all is well then the readout starts only after the shutter has closed, and the readouts are sequential.
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