I get a FITSIO or DAL error when I try to read an event list file. What's happening?
Sometimes a DAL or FITSIO error may occur when an event list file
is opened with
evselect. This is due to the
maximum number of FITS file opening allowed by
cfitsio
being exceeded.
By opening an event list, all the GTI extensions are stored
into temporary files, which remain open until the GTI
extensions get copied to the output products as part
of the data subspace. Although the latest version of
dss
tries to merge as many GTI files as possible, still sometimes
the maximum number may be exceeded.
Unfortunately there is no easy workaround for this problem.
The only currently available solution is to locally build
the cfitsio library with a large file number limit.
However, this problem is likely to occur only in SAS low memory mode.
