Trending plot for photometric zeropoints.

Photometric standard star fields are typically only measured when they are needed to calibrate science observations in clear or photometric nights. There may be more than one measurement per filter and per night if the science observations require photometric conditions. The zeropoints plotted on the Health Check pages are averages for each night of the zeropoints from the individual measurements.

The plotted values have been converted from ADU to electrons. Please note that downloaded zeropoints from the database are in ADU. The difference to the plotted values is 2.5 * log10(CONAD).

WARNING: Zeropoints have been computed using constant extinction coefficients and zero color terms, with the main purpose of instrument and site performance monitoring. Though they are reasonably precise, they are not suitable for accurate photometric calibrations.

The FULL plot has M1 coating marked with blue vertical lines, M1 washing with cyan lines (since 2010 only).

Template ID: img_cal_Photom. Pipeline recipes: vmimstandard (individual pointing) / vmimcalphot (averaging).