- ...slit.
- For higher centering accuracy, place the autoguider probe at
its central position (ICL command UAGXY 35540 41200). Then
centroid on the star, move the image to a standard position previously
calculated to correspond to the centre of the slit in both directions.
By repeating this procedure with a temporarily closed shutter (use the
ICL PAUSE UES command followed by CONTINUE UES), proper
tracking can be checked during the exposure.
- ...#figcndcurves>.
-
the general philosophy of filter use is to use main-beam filters to:
- reject unwanted wavelengths (far red for CCD, blue for the IPCS,
all except one order for long-slit work).
- match object flux to detector in use so as to avoid saturation
(mainly a point of consideration with IPCS-II).
Having determined the correct main-beam filter for the science exposure,
these must also be used for calibration exposures.
- ...level.
- If you don't understand this fully, don't try it.