4
$\begingroup$

I'm working on an animation that replicates our Solar System. I know this has been done before, but I'm working on something that requires me to make one myself. With that being said, I'm having a tough time deciphering the JPL Ephemerides. Particularly for the Moon because I have already figured out how to work the VSOP Ephemerides, which gives me the positions for the planets.

Does anyone know of a source I could use to learn how to utilize the ASCII JPL Epehemerides file that are found here? It would be a huge help and I think a step by step walk through would probably help others in the future.

Thanks!

Link to Epheremerides files

$\endgroup$
4
$\begingroup$

There is a python package called Skyfield that loads, reads and interpolates the binary forms of the JPL Development Ephemerides or DEs for you, and does everything else you need to get the absolute best results possible from them. If you can use even a tiny bit of python then this would be the way to go rather than trying to figure out how to interpolate JPL's "special flavor" of Chebyshev polynomials.

See these in Space Exploration SE:

and also see how easy it is to do things like this with Skyfield in this answer to Sunset on [Mountain] from [Viewing Point]

Also this answer to How to calculate the planets and moons beyond Newtons's gravitational force? shows how I used JPL's Horizons interface output (which also interpolates the DEs using Spice) to compare my numerical orbit integrator results to the ephemerides.

And just for fun see How to pronounce “Ephemerides”? in English SE.

| improve this answer | |
$\endgroup$
  • 1
    $\begingroup$ @whathm Sorry, for some reason I missed your first comment. No, the bounty is totally independent of what you would like to choose to accept if you decide to accept anything at all. It's just for a new user who found a really interesting/useful link. $\endgroup$ – uhoh Jun 13 at 23:12
  • 1
    $\begingroup$ @whathm as an aside, the Python package Skyfield is a complete solution, if you are pressed for time and it does what you need, it's an excellent solution. $\endgroup$ – uhoh Jun 13 at 23:14
  • 1
    $\begingroup$ Ahh gotcha. I think I misunderstood how bounties work. You can assign it to any answer regardless of whether the question asker has chosen a solution. Is that correct? $\endgroup$ – whathm Jun 13 at 23:15
  • 1
    $\begingroup$ Aaaand you just assigned it. Hahaha ok, I totally misunderstood them. Sorry about that. $\endgroup$ – whathm Jun 13 at 23:16
  • 1
    $\begingroup$ @whathm no reason to be sorry at all! Comments are for clarification, and Stack Exchange is different than most other sites and takes a while getting used to. $\endgroup$ – uhoh Jun 13 at 23:17
4
+100
$\begingroup$

This link even gives you the algorithm to calculate: link here

Also, if you are comfortable with the VSOP, the VSOP2000 does have the moon data... the ephemerides can be downloaded from here

| improve this answer | |
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.