<p>So I'm looking to replicate the inner Solar System to a decent degree of accuracy. So far I've been utilizing the Keplerian Elements and Equations for the planets, as shown <a href="https://ssd.jpl.nasa.gov/txt/aprx_pos_planets.pdf" rel="nofollow noreferrer">here</a>. There is one issue with this though:</p>

<p>For the Earth and Moon, I only get the path of the Barycenter. This is great, but it means that the next thing I need is the Earth's and Moon's Keplerian Elements relative to their Barycenter. Now I can get the starting element values from <a href="https://ssd.jpl.nasa.gov/horizons.cgi#top" rel="nofollow noreferrer">JPL HORIZONS</a> or the <a href="https://ssd.jpl.nasa.gov/?sat_elem#legend" rel="nofollow noreferrer">JPL Planetary Satellite Mean Orbital Parameters</a>. However, I get a bit stuck on what the best way to evolve these values over time is. </p>

<p>I'm thinking that maybe the answer lies in utilizing the Longitude Rate (<em>n</em>) in the <a href="https://ssd.jpl.nasa.gov/?sat_elem#legend" rel="nofollow noreferrer">JPL Planetary Satellite Mean Orbital Parameters</a> for approximate motion.</p>

<p><strong>Does anyone have any solid resources I could utilize to determine a good solution to this problem (i.e. books/links)?</strong></p>

<p><em>Also, just so I know, does a question like this actually belong here? Or is it more appropriate for <a href="https://space.stackexchange.com/">Space Exploration</a>?</em></p>

CC BY-SA 4.0
2020-06-12T21:42:32.250Z
I believe this question is on topic.
Mike G
CC BY-SA 4.0
2020-06-28T01:41:46.453Z
@MikeG Thanks by the way! Still looking for an answer unfortunately :(
Jee
CC BY-SA 4.0
2020-06-28T11:40:16.950Z
Take a look at https://astronomy.stackexchange.com/questions/36713/where-can-i-get-j2000-epoch-initial-mean-longitudes-for-all-planets-and-celestia and look in Appendix C.1
Huy Pham
<the-moon><earth><natural-satellites><kepler><earths-orbit>
Keplerian Elements for the Moon and Earth around their Barycenter
Jee
# Keplerian Elements for the Moon and Earth around their Barycenter

(Asked by: username_0 on 2020-06-12)

So I'm looking to replicate the inner Solar System to a decent degree of accuracy. So far I've been utilizing the Keplerian Elements and Equations for the planets, as shown [here](https://ssd.jpl.nasa.gov/txt/aprx_pos_planets.pdf). There is one issue with this though:

For the Earth and Moon, I only get the path of the Barycenter. This is great, but it means that the next thing I need is the Earth's and Moon's Keplerian Elements relative to their Barycenter. Now I can get the starting element values from [JPL HORIZONS](https://ssd.jpl.nasa.gov/horizons.cgi#top) or the [JPL Planetary Satellite Mean Orbital Parameters](https://ssd.jpl.nasa.gov/?sat_elem#legend). However, I get a bit stuck on what the best way to evolve these values over time is.

I'm thinking that maybe the answer lies in utilizing the Longitude Rate (*n*) in the [JPL Planetary Satellite Mean Orbital Parameters](https://ssd.jpl.nasa.gov/?sat_elem#legend) for approximate motion.

**Does anyone have any solid resources I could utilize to determine a good solution to this problem (i.e. books/links)?**

*Also, just so I know, does a question like this actually belong here? Or is it more appropriate for [Space Exploration](https://space.stackexchange.com/)?*

**Tags:** the-moon, earth, natural-satellites, kepler, earths-orbit
> **Comments:**
> **username_1**: I believe this question is on topic.  
> **username_0**: @MikeG Thanks by the way! Still looking for an answer unfortunately :(  
> **username_2**: Take a look at https://astronomy.stackexchange.com/questions/36713/where-can-i-get-j2000-epoch-initial-mean-longitudes-for-all-planets-and-celestia and look in Appendix C.1  

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