In many ways. Pyephem uses the ancient xephem linux C library for its astronomical calculations for both satellites and solar bodies. Skyfield uses the modern N

In many ways. Pyephem uses the ancient xephem linux C library for its astronomical calculations for both satellites and solar bodies. Skyfield uses the modern NASA SDG4 tables for a more accurate calculation of satellite positions and JPL’s ephemeris tables for planetary positions, yielding much greater accuracy and precision. It is written in pure Python and uses Numpy for speed enhancement. Finally, its API is completely different so knowing pyephem won’t be of much help in learning skyfield.