SNIFS Observing Sequence

SNIFS Shutter and CCD Readout Sequence

The observing sequence for any science observation needing guiding, assuming a common shutter is as follows: If guiding is not required, then the first three steps can be omitted. For some calibration observations it is may not be necessary to read all 3 CCD's. If we wish to allow different exposure times for the spectrograph and the imager, then the spectrograph should also have a shutter. Then there are two operational cases to consider: If (t(imager) < t(spectrograph)): If (t(imager) > t(spectrograph)): For a long sequence of observations with difference exposure times, the ordering of these two cases will eventually

SNIFS Calibration Components

Here is an example of the types of calibration we would like SNIFS to obtain. In making this list, I've assumed that all options are open. The amount of calibration might be excessive, but since we won't be reducing it by hand it can't hurt. Non-standard calibration which might require some explaination includes: Types of Calibration:

SNIFS Suggested Observing Sequence

Greg Aldering (
last updated Feb 28, 2001