PNS MANUAL: Taking Flux standards
How to take exposures of flux standards
The PNS shutter is rather slow. For calibration of the photometry with bright flux standards the shutter would introduce large uncertainties. The procedure described below involves leaving the shutter open, and letting the CCD integration time determine the exposure time. As the CCDs are windowed, the beginning of the readout is a fast parallel transfer of the charges, ensuring accurate photometry on the flux standard.
Perform the following commands, in sequence:
- Once target acquisition is complete, make sure A&G mirror is OUT
(check A&G mimic display). If it is not, issue AGMIRROR OUT on A&G console.
- On PNS console issue SHUTO command (opens shutter).
- On PNS console issue MASKO command if there is doubt the mask may be in.
- On DAS console issue fluxstd time "title" (performs a readout of time seconds). 20 seconds on an 11th mag star works well.
- When finished, issue SHUTC command on PNS console to close shutter.
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Last updated 19-07-2001
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