Software Tools

The software tools developed by the ACS Team can be categorized into two broad classes: calibration tools and analysis tools. The calibration tools are intended for the correction of detector effects seen in the three ACS channels (e.g. bias and dark subtraction, flat-field divison etc..). The analysis tools come in two forms, guided examples or webtools. The guided examples provides users with a jupyter notebook demonstrating how to complete typical tasks they will encounter when analyzing ACS data (e.g. zeropoint calculations for absolute photometry), as well as, atypical tasks such as dark subtracting the SBC or running the CTE forward modeler. The webtools are designed to provide users with an easy interface to  handle complicated tasks such as computing zeropoints or performing a photometric CTE correction. 

The calibration of detector effects (e.g. bias subtraction, dark subtraction, flat-fielding) is handled by the ACS calibration pipeline, CALACS. CALACS is packaged together with the various calibration pipelines used by each of the instrument teams (e.g. CALCOS, CALSTIS, and CALWF3) into single software package called HSTCAL. This package is distributed via the AstroConda Channel maintained by the Space Telescope Sciene Institute. The CALACS package is written entirely in C and the complied executables may be run from the command line. For users more comfortable working in python, the ACS Team developed the python package, ACSTOOLS, which is a wrapper around the underlying CALACS executables. 

When analyzing ACS data, there are many things to consider depending on the analysis performed and the dataset being used. The ACS Team has identified some of the most common problems users face during this process and created a series of jupyter notebooks and webtools to address them. The notebooks are essentially "HowTo" articles that show you how to solve each problem in an interactive manner. They have minimal dependencies and are intended to run in the standard astroconda environment. The webtools are standalone applications that can be accessed from anywhere and have no dependencies.