Observation Planning (astroplan)

What is astroplan?

astroplan is an open source Python package to help astronomers plan observations.


This release should be considered a “preview”, as Astroplan is still under heavy development. Most importantly for users, this means the astroplan API may change suddenly and without warning, like the weather. Consider using Astropy, PyEphem and/or Skyfield if you’re looking for some of the functionality here but want to use more mature packages.

The goal of astroplan is to make a flexible toolbox for observation planning and scheduling. When complete, the goal is to be easy for Python beginners and new observers to to pick up, but powerful enough for observatories preparing nightly and long-term schedules.


  • Calculate rise/set/meridian transit times, alt/az positions for targets at observatories anywhere on Earth
  • Built-in plotting convenience functions for standard observation planning plots (airmass, parallactic angle, sky maps).
  • Determining observability of sets of targets given an arbitrary set of constraints (i.e., altitude, airmass, moon separation/illumination, etc.).
  • Astropy powered!



  • Christoph Deil
  • Stephanie Douglas
  • Eric Jeschke
  • Adrian Price-Whelan
  • Erik Tollerud
  • Brigitta Sipocz
  • Karl Vyhmeister