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                                    NUSTAR
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NuSTARDAS v2.1.4:

This update provides preparatory software in case of a future failure
of one of the NuSTAR metrology lasers used to reconstruct the mast
motions. There is no current danger of either laser failing. This
code update will only be used if the NuSTAR SOC begins delivery of
synthetic mast files as described in Earnshaw et al. (2022)
(https://doi.org/10.1117/1.JATIS.8.1.014009). Otherwise, users
should notice no difference in the behavior of NuSTARDAS.

- nupipeline:

  Added a new hidden input parameter 'check_metsim_files' (default
  value set to 'yes', no need to set it in the command line) 

  if 'check_metsim_files=yes':  checks for the presence of the mast
  and psdcorr _sim0/1.fits files in the input 'event_cl' directory
  (these files will only be delivered in the case of a metrology
  laser failure) 

  if 'sim0/1' files are found: automatically sets internally
  runmetrology=no and uses the predictive mast and psdcorr _sim0/1.fits files 

  if 'sim0/1' files are not found: if runmetrology=yes generates
  internally the mast and psdcorr files; if runmetrology=no uses
  the "nominal" mast and psdcorr files 

  if 'check_metsim_files=no' (needed to be added to the command line):
  the data processing scheme is unchanged. In particular, if the mast
  and psdcorr _sim0/1.fits files are present in the input 'event_cl'
  directory, they are ignored 
  
  if 'runmetrology=no': copies in the output directory the mast and
  psdcorr files (parameters 'inmastaspectfile' and 'inpsdfilecor') 
  
- nuproducts: automatically checks for the presence of the
  mast _sim0/1.fits file in the input directory and, if present,
  uses it internally. If the _sim0/1.fits mast aspect file is not
  found, uses the nominal mast.fits file. 

From the user's point of view, the usage of the two modules is
unchanged. In the case of a failure of one of the two metrology
lasers, both 'nupipeline' and 'nuproducts' will automatically use
the sim0/1 files from the archive 'event_cl' directory which will
be delivered in the event of a metrology laser failure, with no
need to change the command line or update the code and/or the CALDB.