Fast Photometry

This observing mode is for time-series photometry.
  1. It uses a mask located at the top part of the FoV (left-side panel of the top figure).
  2. And executes a series of exposure and CCD parallel-shift without reading-out the CCD image.
  3. After a fixed number of exposure+shift, it readouts the CCD image (right-side panel).
  4. The width of the slit and number of pixel-shift can be adjusted.
  5. Overhead between exposures is about 3.2 seconds.
The purpose of this observing mode is to reduce the overhead between exposures. In the above example, there is 3.2 seconds overhead between exposures and it takes
    { (3 sec exposure) + (3.2 sec overhead) } * 60 + (23 sec readout for 2x2 binning) = 6.7min.
to take one image with 3x60=180sec=3min. integration.
If you use longer exposure time, the fraction of overhead will be reduced.

Please contact the Support Astronomer if you need further information.



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