  We present astroplan - an open source, open development, Astropy affiliated
package for ground-based observation planning and scheduling in Python.
astroplan is designed to provide efficient access to common observational
quantities such as celestial rise, set, and meridian transit times and simple
transformations from sky coordinates to altitude-azimuth coordinates without
requiring a detailed understanding of astropy's implementation of coordinate
systems. astroplan provides convenience functions to generate common
observational plots such as airmass and parallactic angle as a function of
time, along with basic sky (finder) charts. Users can determine whether or not
a target is observable given a variety of observing constraints, such as
airmass limits, time ranges, Moon illumination/separation ranges, and more. A
selection of observation schedulers are included which divide observing time
among a list of targets, given observing constraints on those targets.
Contributions to the source code from the community are welcome.
