I'm currently trying to write a C++ library that makes accessing binary data from a JPL ephemeris file easier. So far I sifted through the web, trying to find a good and thorough documentation about what is actually stored in there and how to work with the data.

Does anybody know of a PDF/Book or something similar, that explains anything of that sort?

Thanks in advance!

  • $\begingroup$ I just ran across this question - you may find some of the various answers there helpful as well. $\endgroup$
    – uhoh
    Mar 19 '17 at 18:03

Be aware there are differing formats. SPK is the newer format - the older text format seems to be deprecated.

It's worth having a look at the documentation on this jplephem python library as it explains the format reasonably well. If you do use SPK, you'll need to read all of the documentation in NASA's SPK repository

I'm not sure if this is from the same author as this library - worth a read as it discusses the FITS format.

  • $\begingroup$ The python library is really good! Thanks a lot! $\endgroup$
    – lindebear
    Mar 13 '17 at 13:18

The Python package Skyfield was written fairly recently, from scratch, by the same person who maintains PyEphem. You may find helpful information inside there as well.

I had some difficulty reading a JPL kernel with a variant format, and was pointed to a home-brew python package that solved my problems. The whole thing is described here.

If you look at the candid comments here: https://github.com/whiskie14142/spktype01 you'll notice that the task is not always transparent.

There is also the helpful SPK Required Reading.


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