CALSTIS was scaling the superdark prior to dark subtraction by multiplying it by the 'dark time' and the total exposure time. However, the 'dark time' was already taken into account in the pipeline superbias; therefore, CALSTIS was applying the dark time correction twice. CALSTIS 1.4 has been modified to scale the superdark prior to dark subtraction with the total exposure time only.
Corrections have been made to the sections of the CALSTIS code that perform 2-D rectification and 1-D spectral extraction. These include:
- Ignoring the value of the keyword SDQFLAGS when performing background and spectrum extraction to include all the input pixel values in the calculation.
-
Checking the X2DCORR calibration switch before determining
the MSM offset to prevent accidentally calculate the offsets on a
flat-fielded file instead of the 2-D rectified file.
- Correction
to the 2-D rectification code that was erroneously
multiplying the absolute flux values by the aperture throughput
from the APERTAB table for the extended source case.
- Finding
the shift in the dispersion direction by convolving
the template spectrum with a rectangle of the same width as the
slit used for the WAVECAL observation.
- Increasing
the search range when finding the spatial shifts from
the ends of a long slit or from the edges of occulting bars.