PS1 / IPP Time Errors

  • MJD-OBS (a TAI value in smf files) did not have the 2012.07.01 leap second in files for exposures after 2012.07.01 and processed between 2012.07.01 and 2012.11.09. SHUTOUTC is OK.
  • Between 2015.04.26,16:45 HST and ~2015.05.12,12:00 HST the clocks on the camera readout computers drifted out of NTP lock, accumulating ~113s before the problem was fixed. A table of corrections for the affected images was produced by Craig Rae by using information from one camera computers which did not drift.
  • From 2015.07.01 to 2015.08.11, some IPP machines received a corrupted version of /etc/localtime, which resulted in incorrect values for SHUTOUTC for data processed on those machines. The smf primary header depends on the XY01 chip, so a fraction of the smfs in this period have the wrong SHUTOUTC values.