Checklist for PNS-III

(revised 15 February 2000, minor rev Sep 2001)

See also the observatory checklists WHTchecklist and TNGchecklist

1. CALIBRATION (see the MANUAL for a cookbook of procedures, also OPERATIONS file)
   1. How do we perform flat-fielding, to allow PN magnitudes to be found?
      A white light flat field will be the vignetting function of the instrument convolved with the filter profile (converted from angstrom to pixels using the instrument dispersion) - how do we disentangle them? To put this another way: how do we measure the vignetting which corresponds to a given path through the collimator and through the camera?
2. DETECTORS
   1. Are CCDs always guaranteed to be perpendicular to the beam or do we need tilt adjustment?
      The WHT dewars have tilt and limited piston adjustment built-in, so we just need a kinematic mount for them. The situation at the TNG is unknown, but is likely to be different. Best would seem to be an intermediate flange for each of the two sites, of sufficient thickness that we can allow for differences in dewar specifications
3. OPTO-MECHANICAL
   1. Thermal expansion - effect on image quality and position
   2. How do we focus - moving the camera or moving the dewar? And do we refocus the telescope to correct drift?
      This depends in part on thermal expansion and optical tolerances. At any rate (mail to JH 18/1/1999), it is the position of the CCD which is likely to vary, so the grating-camera distance should be kept constant (having been set once).
   3. Nitrogen flushing - also during operation - is strongly desirable. No special action required at design stage.

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