Python satellite tracking with Orbitron, pyephem- positions not matching

Question

In reading TLE and calculating the orbit of satellites, does PyEphem regard the earth as the sphere or as the ellipse ?

Answer 1

The underlying astronomy library beneath PyEphem is named libastro, and here is its code for doing satellite computations:

https://github.com/brandon-rhodes/pyephem/blob/master/libastro-3.7.5/earthsat.c

It looks like it simply considers the Earth a sphere; the only place that I see the shape of the Earth even coming into the calculation is where the height is produced from its distance from the Earth's surface, where it just uses a constant radius instead of anything fancier:

#if SSPELLIPSE
#else
    *Height = r - EarthRadius;
#endif

So I think your answer is “sphere.”