  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.

Instrumentation and Methods for Astrophysics