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Photometric Observations

The procedure for photometric observations with TurPol is the same as for linear or circular polarimetry. After pointing the telescope, centring the object in the diaphragms, and starting auto-guiding, a sky sample should be taken and then an integration can be started with the INT command in PP.

Note that for photometry, the calcite plate has to be removed from the beam by pushing the knob on the polarimeter IN. Note that in this mode only one of the diaphragm images on the TCS screen will contain the star; the other has only sky signal.

Standard stars have to be observed regularly during the night, well spread out over air masses equal to those of the science objects, and over spectral types, to get a good solution for the night. This is needed both for the extinction, and for the transformation to the standard system. For equations see Appendix 6.2.

Lars Freyhammer
Wed Oct 27 18:02:24 ACT 1999