NuSTAR CALDB Release Version: 20210210
 
Release Type: CALDB release
 
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Contents:
fpm/caldb.indx
fpm/index/caldb.indx2021XXYY
fpm/bcf/instrument/nuCabsparBe20100101v001.fits
fpm/bcf/align/nuCalign20120101v001.fits
fpm/bcf/align/nuCalign20130515v001.fits
fpm/bcf/align/nuCalign20140927v001.fits
fpm/bcf/align/nuCalign20160209v001.fits
fpm/bcf/align/nuCalign20170624v001.fits
fpm/bcf/align/nuCalign20181201v001.fits
fpm/bcf/align/nuCalign20190510v001.fits
fpm/bcf/align/nuCalign20191017v001.fits
fpm/bcf/align/nuCalign20200325v001.fits
fpm/bcf/align/nuCalign20200901v001.fits
fpm/bcf/clock/nuCclock20100101v116.fits
 
 
 
Summary of changes:
 
ALIGNMENT:
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The NuSTAR astrometry has been improved by bringing the source positions on the FPMs into better agreement with one another and closer to the J2000 source coordinates. The update is in the CALDB only in the form of time dependent alignment files and requires the rerun of nupipeline to activate. The update affects source position of events only and not the energy. The update primarily improves observations taken after August 2017, but also adds some improvements across the entire mission lifetime. Before 2017, the astrometric improvement is on the order of a pixel (~2.5"). After, 2017, the adjustment of the source coordinates steadily increases from one pixel in 2017 up to a possible 4-5 pixels (8 - 10") in late 2020.
 
CLOCKFILE:
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This release includes a new release of the CLOCKFILE, v116
 
This is an update of the NuSTAR clock correction file. Details and comparisons to the previous clock correction file can be found here:
http://www.srl.caltech.edu/NuSTAR_Public/NuSTAROperationSite/clockfile.php
The clock correction file keeps the NuSTAR relative time (after barycentric corrections) accurate to better than 100 microseconds and accounts for drifts in the NuSTAR clock caused by temperature variations.
This clockfile is compatible with the current version of barycorr. See the above link or the barycorr fhelp file for its usage.
Due to the nature of the clockfile correction, we note that the timing solution may improve for the ~14 days prior to the generation of the clockfile as more data are incorporated into the fit. For high precision timing of very recent observations we recommend either waiting for the next clock file update or contacting the NuSTAR SOC for assistance.

BE WINDOW:
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We have included a file describing the attenuation due to the beryllium window covering the detectors. This file is useful for some users performing analysis of stray light (either stray light due to the cosmic X-ray background or stray light due to off-axis, bright X-ray sources) but is not directly used by NuSTARDAS.