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CALSTIS V2.17b and V2.18 Release Notes
CALSTIS Version 2.18 was released on 2005-April-01 in the new
STSDAS patch release, Version 3.3.1, which can be found on the
STSDAS Download Page. Some of the features included in this version were
installed in the OTFR pipeline on January 24, 2005 under version CALSTIS 2.17b.
The differences between version 2.17b and 2.18 correct some errors produced
intermittently at run time in some operating systems. These errors have not
been observed in STScI OTFR pipeline, and users should no see differences in
the data obtained from the Archive or calibrated locally with Version 2.18.
The following OPRs are implemented in the release of CALSTIS 2.17b and 2.18:
CALSTIS 2.17b
| OPR 53062: | Uninitialized blaze shift correction flag in CALSTIS7 |
| OPR 52733: | Check number of points before doing polynomial fit in calstis6 |
| OPR52766: | Remove binning factor from slit tilt correction in calstis7 |
| OPR52666: | Calstis6 and calstis7 typo in an if statement |
CALSTIS 2.18
| OPR 52813: | CALSTIS indexing error when reading values from a string |
| OPR 51667: | CALSTIS mkfringeflat should process data containing subarrays |
Related OPR in build OPUS 15.5:
| OPR 51956 | CTECORR keyword should not be in STIS MAMA data files |
OPR 51567
OPR 50663: | Make EPC files available to OTFR
OTFR should use
EPC files during processing |
| OPR 49129: | FLATCORR should be PERFORM for STIS slitless spectroscopic data |
| OPR 48984: | Remove STIS keyword WBIAFILE |
OPR 53062: Uninitialized blaze shift correction flag in CALSTIS7 (in CALSTIS 2.17b)
Uninitialized calibration keywords BLAZECORR for first-order data produced an error under
Solaris 9. Blaze shift correction applies only to echelle data. If the uninitalized variable
results in a value of 1 (i.e. PERFORM), Calstis7 will try to apply the blaze shift
correction. The problem was corrected by setting this value to OMIT for first-order data.
OPR 52813: CALSTIS indexing error when reading values from a string
An indexing error in strtor.c, the function in the lib subdirectory that reads
floating-point values from a string, produced an error in the cosmic-ray rejection
step to read the sigmas from
the crsigmas string. The number of values read from the string is the
number of iterations, and the values are used in the criterion for
identifying cosmic rays. When running under Linux, however, strtor.c returned two values,
sigma = 5 and 0;
almost all pixels were rejected as "cosmic rays" in the second
iteration because sigma was zero. This was due to an
indexing error, i.e. it was reading beyond the end of the string, and the
character at that point happened to be a blank, which was converted
to zero by the atof() function in the C library. The character that
is found at that location will depend on the operating system.
OPR 52733: Check number of points before doing polynomial fit in calstis6
(in CALSTIS 2.17b)
In the background subtraction step in calstis6 for first-order MAMA data,
a low order polynomial is fit to the background in order to smooth it.
For FUV data there are two telluric emission lines that will extend into
the background, and these are excluded when doing the fit so as to avoid
distorting the fit. The width of the excluded regions depends on the
slit width. When the slit is one of the full apertures, e.g. F25NDQ2,
all of the background data would be excluded from the polynomial fit.
The function in calstis6 that does this fit does not check that the
number of input data points is sufficient for the degree of polynomial
that was specified; this is only caught when it is found that the
matrix is singular.
The problem was solved by including a test to check that the
number of input points is
larger than the degree of the polynomial that is to be fit. If there
are not enough points, a unique error code is returned. If there are too few points
and the detector is the FUV, then a warning
message is printed and background smoothing is not done.
OPR 52766: Remove binning factor from slit tilt correction in calstis7
(in CALSTIS 2.17b)
Calstis7 includes a correction for the tilt of the aperture with respect to the tilt
of the reference aperture (see OPR 50171). The expression for the correction includes
a factor that depends on the relative binning in the dispersion and cross dispersion
directions. When this is run on data taken with the reference aperture, the correction
for tilt should be zero; however, for data that were binned by two in the dispersion
direction, the resulting 2-D rectified image was rotated by about 0.15 degrees, half
the angle of the reference slit. Therefore, the factor depending on binning has to be
converted to unbinned pixels before multiplying by del_tan, the difference between the
tangents of the
angle of the aperture and the angle of the reference aperture.
OPR 52666: Calstis6 and calstis7 typo in an if statement (in CALSTIS 2.17b)
There was an "if" statement in cs6/newtrace6.c and cs7/newtrace.c that contained a typo.
The typo introduced a statement that, although harmless, was unnecessary and misleading;
so it was removed.
OPR 51667: CALSTIS mkfringeflat should process data containing subarrays
The STIS STSDAS mkfringeflat tasks (prepspec, normspflat, mkfringeflat, and
defringe) couldn’t handle subarrays and binned spectra.
It was modified to identify and process images
containing subarrays and binned spectra. The binning can be in either
the dispersion or cross-dispersion directions, or both.
OPUS 15.5 release OPRS
OPR 51956: CTECORR keyword should not be in STIS MAMA data files
CTECORR header keywords were erroneously populated for MAMA data files. It only
applies to CCD data.
OPR 51567/50663: CALSTIS Make EPC files available to OTFR/OTFR should use EPC
files during processing
ETC files are made available to the OTFR pipeline to be used with CALSTIS.
OPR 49129: FLATCORR should be PERFORM for STIS slitless spectroscopic data
FLATCORR is currently set to OMIT for STIS slitless spectroscopic data.
It is also set to OMIT for prism observations. The reason for turning
off FLATCORR was that the flat field is somewhat wavelength dependent;
slitless data could have multiple objects in the field, and the prism
dispersion is very different from that of the gratings. The wavelength
dependence is a secondary effect, however, compared with the pixel-to-
pixel variations. Therefore, FLATCORR is now set to be performed for slitless
and for prism observations.
OPR 48984: CALSTIS Remove STIS keyword WBIAFILE
The keyword WBIAFILE in STIS CCD primary headers is supposed to give the
name of the bias file for the wavecal. As of OPUS version 14.3, however,
this keyword is no longer being populated correctly; it has the same value
as BIASFIILE. WBIAFILE is therefore misleading and redundant, and it
was removed from the header.
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