<p>This link even gives you the algorithm to calculate: <a href="https://asd.gsfc.nasa.gov/Craig.Markwardt/bary/" rel="nofollow noreferrer">link here</a></p>

<p>Also, if you are comfortable with the VSOP, the VSOP2000 does have the moon data...
the ephemerides can be downloaded from <a href="ftp://syrte.obspm.fr/francou/vsop2000/" rel="nofollow noreferrer">here</a></p>

CC BY-SA 4.0
2020-06-07T06:31:18.560Z
2020-06-07T06:31:18.560Z
Huy Pham
<p>There is a python package called <a href="https://rhodesmill.org/skyfield/" rel="nofollow noreferrer">Skyfield</a> that loads, reads and interpolates the binary forms of the <a href="https://en.wikipedia.org/wiki/Jet_Propulsion_Laboratory_Development_Ephemeris" rel="nofollow noreferrer">JPL Development Ephemerides</a> 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.</p>

<p>See these in Space Exploration SE:</p>

<ul>
<li><a href="https://space.stackexchange.com/q/12506/12102">What is the exact format of the JPL ephemeris files?</a></li>
<li><a href="https://space.stackexchange.com/q/30579/12102">How is the Chebyshev method used by JPL?</a></li>
<li><a href="https://space.stackexchange.com/q/10490/12102">Is there a way to extract the Chebyshev coefficients for a body from a SPICE kernel?</a></li>
<li><a href="https://space.stackexchange.com/q/34875/12102">How to obtain Chebyshev coefficients directly from the JPL Horizon's interface?</a></li>
<li><a href="https://space.stackexchange.com/q/27834/12102">I've almost learned to spell Chebyshev, why has JPL switched to Hermite interpolation for DE438?</a></li>
</ul>

<p>and also see how easy it is to do things like this with Skyfield in <a href="https://astronomy.stackexchange.com/a/30141/7982">this answer</a> to <em>Sunset on [Mountain] from [Viewing Point]</em></p>

<p>Also <a href="https://space.stackexchange.com/a/23409/12102">this answer</a> to <em>How to calculate the planets and moons beyond Newtons's gravitational force?</em> 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.</p>

<p>And just for fun see <a href="https://english.stackexchange.com/q/370655/217285">How to pronounce “Ephemerides”?</a> in English SE.</p>

CC BY-SA 4.0
2020-06-12T17:45:22.110Z
Is your bounty trying to say that Huy Pham is correct and deserves to be marked as the answer?
Jee
CC BY-SA 4.0
2020-06-13T23:02:29.300Z
Looking for an answer here. I haven't been able to completely verify either answer because I have not had time to do so. So in order to avoid wasting your bounty, I would love to hear your input for which answer you are referring to.
Jee
CC BY-SA 4.0
2020-06-13T23:12:52.810Z
@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.
uhoh
CC BY-SA 4.0
2020-06-13T23:14:35.847Z
@whathm as an aside, the Python package [Skyfield](https://rhodesmill.org/skyfield/) is a complete solution, if you are pressed for time and it does what you need, it's an excellent solution.
uhoh
CC BY-SA 4.0
2020-06-13T23:15:55.683Z
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?
Jee
CC BY-SA 4.0
2020-06-13T23:16:23.233Z
Aaaand you just assigned it. Hahaha ok, I totally misunderstood them. Sorry about that.
Jee
CC BY-SA 4.0
2020-06-13T23:17:40.513Z
@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.
uhoh
CC BY-SA 4.0
2020-06-13T23:18:51.237Z
Understood, thanks! And as for Skyfield. I took a quick look at it and it looks like it'll be super helpful. I'll get back to you as soon as I get around to digging deeper into it. Thanks again!
Jee
CC BY-SA 4.0
2020-06-07T02:40:55.670Z
2020-06-07T02:40:55.670Z
uhoh
<p>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. </p>

<p>Does anyone know of a source I could use to learn how to utilize the ASCII JPL Epehemerides file that are found <a href="ftp://ssd.jpl.nasa.gov/pub/eph/planets/" rel="nofollow noreferrer">here</a>? It would be a huge help and I think a step by step walk through would probably help others in the future.</p>

<p>Thanks!</p>

<p><a href="ftp://ssd.jpl.nasa.gov/pub/eph/planets/" rel="nofollow noreferrer">Link to Epheremerides files</a></p>

<orbit><orbital-mechanics><positional-astronomy><ephemeris>
Understanding the JPL Ephemerides
Jee
# Understanding the JPL Ephemerides

(Asked by: username_0 on 2020-06-07)

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](ftp://ssd.jpl.nasa.gov/pub/eph/planets/)? 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](ftp://ssd.jpl.nasa.gov/pub/eph/planets/)

**Tags:** orbit, orbital-mechanics, positional-astronomy, ephemeris


---

## 2 answers

### Answer by username_1 on 2020-06-07. Score: 4

This link even gives you the algorithm to calculate: [link here](https://asd.gsfc.nasa.gov/Craig.Markwardt/bary/)

Also, if you are comfortable with the VSOP, the VSOP2000 does have the moon data...
the ephemerides can be downloaded from [here](ftp://syrte.obspm.fr/francou/vsop2000/)


---

### Answer by username_2 on 2020-06-07. Score: 4

There is a python package called [Skyfield](https://rhodesmill.org/skyfield/) that loads, reads and interpolates the binary forms of the [JPL Development Ephemerides](https://en.wikipedia.org/wiki/Jet_Propulsion_Laboratory_Development_Ephemeris) 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:

* [What is the exact format of the JPL ephemeris files?](https://space.stackexchange.com/q/12506/12102)
* [How is the Chebyshev method used by JPL?](https://space.stackexchange.com/q/30579/12102)
* [Is there a way to extract the Chebyshev coefficients for a body from a SPICE kernel?](https://space.stackexchange.com/q/10490/12102)
* [How to obtain Chebyshev coefficients directly from the JPL Horizon's interface?](https://space.stackexchange.com/q/34875/12102)
* [I've almost learned to spell Chebyshev, why has JPL switched to Hermite interpolation for DE438?](https://space.stackexchange.com/q/27834/12102)

and also see how easy it is to do things like this with Skyfield in [this answer](https://astronomy.stackexchange.com/a/30141/7982) to *Sunset on [Mountain] from [Viewing Point]*

Also [this answer](https://space.stackexchange.com/a/23409/12102) 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”?](https://english.stackexchange.com/q/370655/217285) in English SE.

> **Comments:**
> **username_0**: Is your bounty trying to say that username_1 is correct and deserves to be marked as the answer?  
> **username_0**: Looking for an answer here. I haven't been able to completely verify either answer because I have not had time to do so. So in order to avoid wasting your bounty, I would love to hear your input for which answer you are referring to.  
> **username_2**: @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.  
> **username_2**: @whathm as an aside, the Python package [Skyfield](https://rhodesmill.org/skyfield/) is a complete solution, if you are pressed for time and it does what you need, it's an excellent solution.  
> **username_0**: 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?  
> **username_0**: Aaaand you just assigned it. Hahaha ok, I totally misunderstood them. Sorry about that.  
> **username_2**: @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.  
> **username_0**: Understood, thanks! And as for Skyfield. I took a quick look at it and it looks like it'll be super helpful. I'll get back to you as soon as I get around to digging deeper into it. Thanks again!  

---

