Using QuickReduce – first steps

Verifying your QuickPreduce and python installation

After installing the QuickReduce pipeline itself and all required packages, you should make sure all packages are installed properly and can be found using the default python executable. To do so, run the script and make sure you don’t get any error messages (see the installation page for details).


General note on parameter passing

As I learned which tracking down some user-problems, python does not handle some OS-specific shortcuts properly. In particular, the ~ as a short-cut to your home-directory does not work, causing some of the parameters to point to non-existing directories and hence some reduction steps to be ignored and completed unsuccessfully. For example, the following won’t work as expected (for this example: the WCS solution generated by the instrument is not understood by SourceExtractor, hence all Ra/Dec values used for the WCS matching are all 0, typically causing the astrometric calibration to fail):

~/quick_reduce/ .... -wcs=~/quick_reduce/2mass_distort5.fits

The initial ~/quick_reduce/ is properly handled by the operation system itself, hence luring you into believing the syntax works at other places as well. The second -wcs=~/quick_reduce… however, will point to a sub-directory names ~ (tilde) in the current working directory, such as


rather than to what you would hope for, i.e.



The solution is simple: Avoid the ~ as short-cuts and spell out the full directory path, i.e.


and you won’t have any problems.