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.

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