Focusing StanCam - a quick help

  1. Stop auto-guiding
  2. Start a focus sequence with the command: focusexpose (focus start-value) (focus step-size) (exptime)
    A good first guess is focusexpose 21950 100 15
    The image should look like this:

  3. Use the sequencer script focus-auto focus-step-size [image] to analyse the image.
    E.g. focus-auto 100

  4. You can also use the Postprocess Imexam to measure the FWHM of the images (use a-key), quite imexam by typing q-key
    Take another focus sequence with finer focus step size if needed.

    If you have problems with the BIAS/imexam you can use iraf/imexam at florence.

    Note, that the telescope focus vs FWHM curve is rather broad around the optimum focus.