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StanCam and NOTCam together

The StanCam web page

StanCam, an optical standby camera with a TEK 1024x1024 back-side illuminated thinned CCD, is in principle always available when NOTCam is mounted. If you plan to use it, please, state so explicitly in your NIRF . StanCam is per default equipped with standard UBVRI filters, the SDSS z' filter and a wide H-alpha filter. To change between NOTCam and StanCam takes a few seconds. In the following we describe how to start-up StanCam when otherwise running NOTCam.

  • Open another desktop on the lisa terminal where you are already logged in on marissa and running NOTCam. Open a terminal window and login on tessa with ssh -l obs tessa, the password being provided by staff.

  • In the tessa terminal window type startobssys stancam. A window will pop up asking for the TCS access code. This code is found on the TCS in status page 1 which you get by typing sh 1 onthe TCS command line. The code is shown on the top part of the screen as: Access Code xxxxxxxxxxx. Type it in. Note that you have to do this every night, as with all instruments.

  • In addition to the two sequencer windows, ds9, the StanCam BIAS CCD status, TCS Status and Postprocess windows will be started up.

  • If you want you may start the electronic observation log: In a terminal window type cd /data/stancam/ followed by obslog-stancam STnnmm\* & where "nnmm" is the image prefix of the night.

  • To setup the TCS correctly for StanCam imaging, in the Sequencer window type: tcs.setup-tel-stancam
    If you wish to know the content of this script, it is explained here. Please, note that the default telescope focus value for StanCam (23040) is used. (Telescope power should be on when you run this script.) The offset when going from NOTCam WF-cam K-band imaging to StanCam R-band is measured to be -380 units.

  • You can select StanCam filter with the command: tcs.ccd-filter N where N gives the filter number (e.g. U=1,B=2,V=3,R=4,... see the present instrument set up) .

  • Adjust the telescope focus, if needed .

  • Make an exposure by typing expose t where t is the time in seconds. Bias images can be taken using the command mdark 0 N where N is the number of images. Take single target exposures or run your scripts.

  • When finished with StanCam go back to NOTCam by typing in the Sequencer window: tcs.setup-tel-notcam
    If you wish to know the content of this script, it is explained here. Note that the default telescope focus for NOTCam (23480) is used, but you might have a better focus obtained from earlier in the night. Set this with the command tcs.focus-position xxxxx

  • When you want to exit from the StanCam Sequencer type shutdownobssys stancam in a terminal window remotely logged in to tessa. Wait for all programs to close.

Note on focusing StanCam.

If a default StanCam focus is good enough then use foc-del on the TCS as indicated above. The focus offset between NOTCam WF-cam K-band and the StanCam R-band filter is 380 units, in the sense that going from NOTCam to StanCam you apply foc-del -380. NB! If you were using the NOTCam HR camera or if you were doing NOTCam spectroscopy, then you first have to set the reference focus on the TCS for imaging with the WF-camera and K-bands, using the command foc-pos 23xxx. (If you don't know this value, then it is recommended to focus StanCam properly as outlined below.)

If you wish to focus StanCam properly, or if you have not yet focused NOTCam for K-band WF-camera imaging for the night, then use a focus star close to zenith (e.g. from the blanks catalog), or your target if appropriate, and find the telescope focus for StanCam according to the following procedure:

  1. Make sure you are NOT autoguiding!
  2. Put in the StanCam filter you want
  3. Type focusexpose start-focus focus-step exp-time in the Sequencer window
    start-focus for instance 22290
    focus-step for instance 80
    exp-time for instance 12
  4. The resulting image gives a number of exposures taken with different focus values. The last exposure is offset by two steps on the CCD. Evaluate which is the best focus by measuring the FWHM and roundness of the point source.
  5. If the seeing is good, you may iterate with a smaller focus-step size (for instance 40).
  6. Set the telescope focus to the best value by typing in the Sequencer window tcs.focus-position xxxxx.
  7. Finally, correct the focus on the guide TV if autoguiding is needed. Start with tv-foc 415 and adjust with steps of 10.

Comments to Anlaug Amanda Djupvik

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