With v4.2, calChecker keeps a memory about open NOK/MISS issues beyond the canonical 7 days, up to the configured value for the calibration&issue memory (lower right corner). This is implemented both for 'science' and for 'cal4cal'.
The following keys are used to define a SCIENCE VISIR setup:
spectroscopy:ins.slit1.wid, ins.grat1.wlen, ins.filt2.name
The following checks are performed:
imaging standard stars should be taken within +/- 2 hr from the science observations
telluric standard stars should be taken within +/- 2 hr and within the airmass difference of 0.2 from the science observation.