Jul 20, 2023

Minimal data files to work with py-skyfield

Skyfield astro/py-skyfield is a Python library for astronomical computations. It depends on various data files to accurately compute moon phases, planet positions, etc. Several issues are raised by these data files

  • If they’re not found in the path of the Loader, they’re downloaded at runtime. Depending on the archive you’re requesting, some files might be very large, causing a long delay directly related to your network bandwidth. In the case of a web server app, you’d cause a timeout on client’s end.

  • They come mainly from 2 sources NASA’s JPL, and the IERS. If one of them is temporarily unavailable, you couldn’t perform any computation.

  • In some countries, or behind some filtering proxies, some hosts may be blocked.

  • These files have an expiration date in a more or less distant future. As a consequence, even if the files are already downloaded in the right path, at each runtime you could possibly have to download one or more files before making any computation using them.

This package provides at least the most common of these assets.

Checkout these related ports:
  • Xworld - Earth as seen from the direction of the sun
  • Xtide - Harmonic tide clock and tide predictor
  • Xplanet - Draw pictures of the earth textured by an image
  • Xphoon - Set the root window to the moon in its current phase
  • Xmoontool - Version of John Walker's classical moontool for X11/Motif
  • Xephem - Interactive astronomical ephemeris program
  • Xeartk - Small demo for tkgeomap
  • Xearth - Set the root window to the image of earth
  • Wmsun - Dockapp that displays the rise and set times of the Sun
  • Wmspaceweather - DockApp that shows the weather at geosynchronous orbit
  • Wmsolar - Dockapp that displays the Solar System viewed from the top
  • Wmmoonclock - Displays the phase of the moon, plus orbital data
  • Wmjupiter - Dockapp that displays information on Jupiter
  • Wmglobe - Neat xearth-like WindowMaker dockapp
  • Weather - Utility to provide current weather conditions and forecasts