Calstis Version 2.16 was released on 2004-Feb-26 in the new STSDAS release, Version 3.2, which can be found at the STSDAS Download Page. This version of CALSTIS has not been installed in the OTFR pipeline and there is no definite date for its installation. Users who want to have their data calibrated using this version have to recalibrate their data locally.

The following OPRs are implemented in the release of CALSTIS 2.16:

OPR 50310:	Problem comparing floating point values in calstis2
OPR 50301:	CALSTIS,tdscorr is not initialized in calstis6
OPR 50171:	CALSTIS, incorrect wavelength calibration in some situations
OPR 50011:	CALSTIS should correctly calculate the Q correction
OPR 49936:	Scattered light algorithm output
OPR 49009:	Correct CCD spectroscopic data for Charge Transfer Efficiency

OPR 50310: Problem comparing floating point values in calstis2

CALSTIS occasionally failed with the rather obscure error message: "illegal input string 'crsigmas'". This error occurs only rarely and only under Linux. It is due to the so-called "excess precision" problem on x86 machines. There was code in CALSTIS that assumed that two floating point variables should test equal if one has just been assigned to the value of the other, but this can fail if one of the variables is in a register (with 10 bytes) and the other variable is in memory (four bytes). The code has been rewritten to avoid the assumption of equality.

OPR 50301: CALSTIS,tdscorr is not initialized in calstis6

An uninitialized variable for the time-dependent sensitivity correction caused CALSTIS to stop with the message that the TDSTAB (but with a blank name) was not found. This error only occurs if the uninitialized variable happens to have the value 1, which should be rare but did occur for one dataset. The variable is now initialized correctly.

OPR 50171: CALSTIS, incorrect wavelength calibration in some situations

calstis7 has been improved by applying a correction for the slit angle. Wavecals taken with the fiducial apertures now produce accurate wavelengths. A new column was added to the aperture description table for storing the slit angles.

OPR 50011: CALSTIS should correctly calculate the Q correction

The Q factor algorithm in calstis6 gave incorrect values for low source flux levels and long exposure times. The corrected algorithm now corrects the mean dark counts and read noise for the extraction width and does not multiply the mean dark counts by the exposure time.

OPR 49936: Scattered light algorithm output

A bug is fixed in the calstis6idt status messages, so that the completion statement is now printed.

OPR 49009: Correct CCD spectroscopic data for Charge Transfer Efficiency

The MEANDARK parameter is now computed using the median instead of the average.
The CTI correction was being applied to the net count rate; it is now being applied to the flux. The gross count rate G used in the computation now includes dark counts and spurious charge. The background count rate B' is per pixel, rather than per 7-pixel extraction region.

No associated OPR

• The description of 'a2center' in the x1d help file was improved, and the connection with 'maxsrch' was described. Descriptions of the parameters 'bksmode' and 'bksorder' were added.
• 'doppinfo' is now included in the list of directories in the mkpkg file.