Upgrading the processing pipeline for the National Park Service Night Skies program

The US National Park Service (NPS) assesses the night sky quality over parks by capturing a series of overlapping images to obtain a mosaic view of the entire night sky. The NPS Night Skies Program has integrated a sequence of scripts and software packages a - "pipeline" - to process and create the hemispherical mosaic images. This processing pipeline is being improved to reduce dependence on commercial software packages, improve management of revisions, and ease distribution of the latest version. The upgraded pipeline is designed for processing the images in three stages: (I) performing data reduction, calibration, and mosaic, (II) modeling the natural sky brightness to separate out light from artificial sources, and (III) deriving sky quality indicators. Currently, stage I is completed and is presented in detail in this report. Stage II and III are in the upgrading process and will be presented in a future report. In stage I, the pipeline applies basic image reduction, pointing registration, photometric calibration, coordinate transformation, and image mosaicking. We implemented new features including auto-logging the processing history, version control through Git and GitHub, team management on source code development, reduction on the number of required proprietary software usage, and setting the primary pipeline language to Python. Once the upgrade is completed, our open source pipeline can benefit other scientists in the similar research field worldwide for processing related sets of data.