Sherpa, Python, and Astronomy. A Successful Co-evolution.

Sherpa is a fitting tool originally developed as part of the Chandra X-Ray Observatory data analysis software, CIAO: its first version was distributed in October 1999. Seventeen years later, Sherpa is a Python package with C, C++, and Fortran extensions, openly developed on GitHub. Although X-Ray scientific drivers remain strong, other projects outside of the X-Ray astronomical domain are starting to use Sherpa as a dependency in their systems and building on its strengths. In this paper we discuss the challenges we faced in incrementally adapting our software and configuration management to the emerging trends in computing, especially within the astronomical community. We describe the tools, technologies, and processes that helped us in this migration.