What Is The Clock Correction File?
The clock correction file keeps the NuSTAR relative time (after barycentric corrections) accurate to ~2 ms and accounts for drifts in the NuSTAR clock caused by temperature variations, etc.
New clock correction files will be produced as the mission continues on a ~monthly basis.
The list below will always be the most up-to-date list of the NuSTAR clock correction files.
The most recent clock correction file will be released at the time of each official CALDB patch, but it is recommended that users download the most recent clock correction file listed below.
IMPORTANT NOTE - The versions of clock correction files v022 to v063 were found to have unphysical discontinuieties in the clock correction. Only versions v066 and later should be used in analysis.
How Is It Used?
barycorr infile=orig.evt outfile=bary.evt orbitfiles=orbit.fits \
clockfile=nuCclock20100101v066.fits ra=123.45 dec=67.89
There is more extensive information in the 'fhelp' file or at the HEASARC NuSTAR FAQ page