• WX2D, MKTRACE and CTESTIS in the STIS package

• MODEINFO in the SYNPHOT package.

Platform Support

Libraries

HSTIO

HST_CALIB

ACS

NICMOS

    Parameter changes:

• The units of histbinwidth were changed so they match the units of the SAA persistence model image.
• The name of the parameter histclip was changed to nclip
  
• Two more legal values were added to the applied output parameter. It will now be set to N/A if the image was not SAA impacted, and to aborted if the task detected nonsensical values and failed gracefully.
  
• The task parameters were reordered so that the thresh parameter appears immediately after fitthresh.
  
• The darkpath parameter is now used to find the reference files only if the SAADFILE keyword is not set in the post-SAA exposure header, or if the file specified there cannot be found.
• Two additional diagnostic files are now created if the alldiags parameter is set. The diag_filenameroot_hist.txt file contains the version of the SAA persistence image histogram data that is actually fit. The diag_filenameroot_gp_iters.txt contains the sequence of coefficients for each iteration in the gauss-poly fit.

• Imagestats is no longer used to determine the domain threshold; instead, a gaussian-polynomial fit is performed to the SAA persistence image histogram (after some data massaging, as in the original IDL prototype). This produces a more robust estimate of the threshold. The final coefficients for the fit are printed to stdout.  Note: This update changes the recommended values for parameters histbinwidth and nclip in the IRAF task parameters.
• The value of SCNAPPLD keyword in the targimage is now checked to ensure the correction is not applied twice to the same file. Text messages inform the user that this is not a good idea.
• The procedure for constructing the persistence model was changed to use a straight median, rather than a sigma-clipped median.
• The exception logic was changed for the case when the high-signal domain contains too few pixels; instead of raising an exception, a warning is now given and the task fails over to use the low-signal domain calculations only.

• Corrected handling of the case when the specified calcimage is not the same as the targimage.
  
• Corrected number of pixels in each domain printed to diagnostic file.
• Corrected bug in reading the previously-existing SAA persistence model file (if readsaaper is set)

STIS

• blaze shift correction
  
  • Two problems need to be fixed for the CALSTIS echelle blaze shift correction. Part of calculating the correction involves finding the observed wavelength at the middle of the reference spectral order.  If the on-board Doppler shift was applied (or for time-tag data), this should be taken out when finding the index into the wavelength array.  (The index also needs to be determined slightly differently for high-res data.)  The second problem has to do with the wavelength array associated with the PCTAB (the correction for finite extraction height).  The blaze shift correction is now applied to the wavelength array without the PCTAB info.
  • The value written to keyword BLZSHIFT is now the average blaze shift over all orders in the output table.
  • A new zero-point offset term has been added to the blaze shift correction.
    
• support for trace rotation as a function of time
  • The STIS team has determined that spectral traces show time evolution. This has been incorporated in new reference files. CALSTIS was changed to implement the rotation of the trace using the new reference files, providing more accurate traces.
• correction for a memory allocation problem when CTECORR is not PERFORM
• support for running x2d on the output of wx2d
  

• WX2D
  

• This task uses wavelets to resample a 2-D spectral image in the cross-dispersion direction so that the spectral trace will be at a constant row number.  The reason for creating this task is that it does a better job with undersampled data than does 'x2d'.  The output from 'wx2d' will not be resampled in the dispersion direction, and it will not be flux calibrated; however, 'x2d' can be run on the output of 'wx2d' in order to perform both of these functions.
  
• CTESTIS
  
  • The  purpose  of  the  ctestis  task  is to correct signal levels of point-like sources in  photometry  tables  measured  from  STIS CCD images  for  charge loss due to imperfect Charge Transfer Efficiency (CTE). The algorithm used to correct for CTE-induced signal loss  is the  one  published in Goudfrooij, Bohlin, Maiz-Apellaniz, & Kimble, 2006, PASP, October 2006 edition (astro-ph/0608349).  The values of CTE  loss  derived  using this algorithm should be accurate to about 3% RMS (tested for data taken between March 1997 and  August  2004).
    
• MKTRACE
  • This task refines the traces in a trace table based on a science spectrum and its grating and central wavelength. A trace is generated from a science file by fitting a gaussian to each column.  The two traces bracketing the computed trace center are  extracted from the trace table and interpolated. The correction is computed as the difference between the weighted linear fits to the science trace and to the interpolated trace. The correction is applied to all traces in the trace table with that particular OPT_ELEM and  CENWAVE.  An updated trace table is then written out to the current  directory.

Synphot

• wavelength tables for COS observing modes were added to the SYNPHOT data files, and
• WFC3 data range in wavecat.dat was modified to span from 1750-18000A, while adding special
  ranges for WFC3 gratings G280, G102 and G141.
  

ANALYSIS

PyDrizzle

• When the distortion coefficients include a "flip", the computed overlap with kernel='square' now works instead of returning zero for the pixel overlaps.
• The IRAF interface code was revised to automatically update the version parameter based on the version of the Python code.
• The additional offset of 1,1 when the user specifies the output frame (RA, Dec, size, scale and/or orientation) was removed.