This is instrument performance plot for the extinction corrected photometric
zeropoints (at airmass X=0), derived from photometric standard
star calibration frames observed in J filter.
On 2016-11-19 new, CASU pipeline was adopted (green vertical
line), which uses revised method for calculating zeropoints. It takes
into accout DET.NDIT in the total observing time (DET.DITxDET.NDIT)
rather than DET.DIT as was done by the previous pipeline. To
bring the values to the same level, the CASU zeropoints are
corrected by
"+ 2.5 * log10(NDIT)" in this plot. Only data taken with DET.NDIT=5 are plotted.
The reference values for each detector are currently identical to the median of the measured values.
Fig. 1. chip4: The zeropoints for chip #4. Reference value: 26.4 mag
Fig. 2. chip3: The zeropoints for chip #3. Reference value: 26.4 mag
Fig. 3. Average: The zeropoints averaged over all detectors.
This view is sensitive to common changes. Reference value: 26.4 mag
Fig. 4. chip1: The zeropoints for chip #1. Reference value: 26.4 mag
Fig. 5. chip2: The zeropoints for chip #2. Reference value: 26.4 mag
Fig. 6. Scatter View: The standard deviation of the zeropoints, obtained from the sample of all detectors.
This view is sensitive changes of individual detectors.
Major M1 mirror recoating events are marked with a blue vertical bar.