Are there two-line element sets for the moon and/or sun?
The short answer to this question is no. Assumptions made in the SGP4/SDP4 orbital model—made to reduce the computational burden of tracking thousands of earth satellites—are completely invalid when applied to other celestial bodies. Details on why this is so were covered in the January/February 1997 issue of this column titled—naturally enough—”Tracking the Sun and the Moon.” If you want to track the sun, moon, planets, or the latest comet, you’re going to need to use an orbital model specifically designed to track these objects.
