A tarball containing acstools, this documentation, and test data is available at http://stsdas.stsci.edu/download/acstools_nvidia/acstools_nvidia.tar.gz.
Requirements:
With the above requirements installed run the following commands at the command line:
cd acstools
python setup.py build
python setup.py install
If all of the above steps run correctly acstools should now be installed, which you can test by typing import acstools at the Python interactive prompt.
Running the CTE correction is simple using the acstools.PixCteCorr.YCte function. An example from the Python interactive prompt:
>>> import acstools.PixCteCorr as pcc
>>> pcc.YCte('jb1f89eoq_flt.fits')
This will make an output file called jb1f89eoq_cte.fits. The output file name may also be specified:
>>> import acstools.PixCteCorr as pcc
>>> pcc.YCte('jb1f89eoq_flt.fits','corrected_output.fits')
Use the Python help function to see more information on YCte:
>>> import acstools.PixCteCorr as pcc
>>> help(pcc.YCte)
As a convenience we have included scripts called run_correction.py in each of the data directories that can be used to run the CTE correction. Run them by typing python run_correction.py at the command line.
Installed along with acstools is a script called fitsdiff, which is useful for comparing FITS files:
fitsdiff -c '*' -k '*' jb1f89eoq_cte.fits jb1f89eoq_cte_ref.fits
fitsdiff: 1.5 (28 Feb 2011)
file1 = jb1f89eoq_cte.fits
file2 = jb1f89eoq_cte_ref.fits
Keyword(s) not to be compared: ['*']
Keyword(s) whose comments not to be compared: ['*']
Column(s) not to be compared: ['']
Maximum number of different pixels to be reported: 10
Data comparison level: 0.0
Primary HDU:
Inconsistent occurrence of keyword jb1f89eoq_cte.fits has 58, jb1f89eoq_cte_ref.fits has 57
Inconsistent occurrence of keyword HISTORY jb1f89eoq_cte.fits has 34, jb1f89eoq_cte_ref.fits has 35
Input files have naught dimensions
IMAGE Extension 1 HDU:
There are 0 different data points.
IMAGE Extension 2 HDU:
There are 0 different data points.
IMAGE Extension 3 HDU:
There are 0 different data points.
IMAGE Extension 4 HDU:
There are 0 different data points.
IMAGE Extension 5 HDU:
There are 0 different data points.
IMAGE Extension 6 HDU:
There are 0 different data points.
The -c '*' -k '*' options tell fitsdiff not to compare header keywords or comments since we are just interested in whether the data match. Type fitsdiff -h at the command line to see the full help text. In this case we are also not interested in the results about the “Primary HDU”. Rather we are making sure that for each “IMAGE Extension # HDU” there are 0 reported differences.
For convenience we have included scripts called run_comparison.py in each of the data directories that will run fitsdiff as in the above example. Run them by typing python run_comparison.py at the command line.