<p>From inspecting the <a href="https://ssd.jpl.nasa.gov/planets/eph_export.html" rel="nofollow noreferrer">JPL ephemeris website</a>, the ephemeris with the longest time span as of this writing is <a href="https://iopscience.iop.org/article/10.3847/1538-3881/abd414" rel="nofollow noreferrer">DE441</a>, which spans from August 15th, -13200 to March 15th, 17191. It is less accurate than DE440 (which covers the time span 1550-2650 AD), but is more stable over long time periods. For reference, between the years 1970-2020 the difference between DE441 and DE440 is less than 2 meters.</p>
<p>You can access this ephemeris using astropy. For example, I prepared the following script from <a href="https://docs.astropy.org/en/stable/coordinates/solarsystem.html" rel="nofollow noreferrer">astropy's tutorial</a>, evaluating the Moon's position for Julian year -3000. The script will take a while to run the first time (since it needs to download the ephemeris), but subsequent runs will be much faster.</p>
<pre><code>import numpy as np
import matplotlib.pyplot as plt
import astropy.units as u
import astropy.time
import astropy.coordinates
import astropy.visualization

astropy.visualization.quantity_support()
astropy.coordinates.solar_system_ephemeris.set('de441_part-1')

time_stop = astropy.time.Time('-3000', format='jyear')
time_start = time_stop - 27 * u.day
time = np.linspace(time_start, time_stop, num=1000)

location = astropy.coordinates.EarthLocation.from_geocentric(0 * u.m, 0 * u.m, 0 * u.m)

coords = astropy.coordinates.get_moon(time, location).cartesian

plt.figure(figsize=(9, 9))
plt.gca().set_aspect('equal')
plt.plot(coords.x, coords.y)
plt.scatter(coords[~0].x, coords[~0].y)
plt.savefig('moon.png')
</code></pre>
<p><a href="https://i.sstatic.net/rsrkQ.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/rsrkQ.png" alt="Moon orbit for the year -3000" /></a></p>

CC BY-SA 4.0
2022-10-02T05:52:41.903Z
2022-10-02T20:28:57.833Z
2022-10-02T20:28:57.833Z
Roy Smart
<p>I'm aware of the <a href="https://ssd.jpl.nasa.gov/tools/orbit_viewer.html" rel="nofollow noreferrer">NASA orbit viewer</a> but it limits you to years &gt; 1600 AD.</p>
<p>Is there an orbit viewer for any date?</p>

CC BY-SA 4.0
2022-09-30T19:40:46.150Z
Not for "any" date. In the very long term the solar system is chaotic and the exact positions of objects aren't known.
James K
CC BY-SA 4.0
2022-09-30T20:45:58.380Z
@JamesK I was only looking for the moon.
Bob
CC BY-SA 4.0
2022-09-30T21:04:49.727Z
Okay, so please edit the question.  It is possible that something like NASA Horizons will actually tell you want you want to know.  It's not an orbit viewer, but it does use multi-body methods to make accurate longer term predictions.
James K
CC BY-SA 4.0
2022-09-30T21:59:42.727Z
The answer to your question is no, at least not one that has correct positions. This is like asking "Is there an abacus that can add any two numbers?" In order for your question to have a reasonable answer, I'd recommend you ask something like "How far into the past and future has the Moon's motion been calculated *with some degree of accuracy?*" Once you have an answer to that question, you can ask a follow-up question about how to put those calculations into some orbit viewer.
uhoh
CC BY-SA 4.0
2022-10-01T03:12:44.337Z
That NASA orbit viewer page warns you that it's quite crude. "For accurate ephemerides, please instead use our Horizons system. This orbit viewer was implemented using two-body methods, and hence should not be used for determining accurate long-term trajectories (over several years or decades) or planetary encounter circumstances". The [Horizons time span](https://ssd.jpl.nasa.gov/horizons/time_spans.html) for the Sun, Earth, and Moon covers 9999 BC to 9999 AD.
PM 2Ring
CC BY-SA 4.0
2022-10-01T03:19:50.530Z
FWIW, we have very good parameters for the Moon's current orbit, primarily due to [LLR](https://en.wikipedia.org/wiki/Lunar_Laser_Ranging_experiment), but accurately calculating the lunar orbit via traditional analytical methods is [rather complicated](https://en.wikipedia.org/wiki/Lunar_theory). I have a basic 3D orbit plotter in Python using Horizons [here](https://astronomy.stackexchange.com/a/49823/16685).
PM 2Ring
<orbit><software>
orbit viewer for any date for moon
Bob
# orbit viewer for any date for moon

(Asked by: username_0 on 2022-09-30)

I'm aware of the [NASA orbit viewer](https://ssd.jpl.nasa.gov/tools/orbit_viewer.html) but it limits you to years > 1600 AD.

Is there an orbit viewer for any date?

**Tags:** orbit, software
> **Comments:**
> **username_1**: Not for "any" date. In the very long term the solar system is chaotic and the exact positions of objects aren't known.  
> **username_0**: @JamesK I was only looking for the moon.  
> **username_1**: Okay, so please edit the question.  It is possible that something like NASA Horizons will actually tell you want you want to know.  It's not an orbit viewer, but it does use multi-body methods to make accurate longer term predictions.  
> **username_2**: The answer to your question is no, at least not one that has correct positions. This is like asking "Is there an abacus that can add any two numbers?" In order for your question to have a reasonable answer, I'd recommend you ask something like "How far into the past and future has the Moon's motion been calculated *with some degree of accuracy?*" Once you have an answer to that question, you can ask a follow-up question about how to put those calculations into some orbit viewer.  
> **username_3**: That NASA orbit viewer page warns you that it's quite crude. "For accurate ephemerides, please instead use our Horizons system. This orbit viewer was implemented using two-body methods, and hence should not be used for determining accurate long-term trajectories (over several years or decades) or planetary encounter circumstances". The [Horizons time span](https://ssd.jpl.nasa.gov/horizons/time_spans.html) for the Sun, Earth, and Moon covers 9999 BC to 9999 AD.  
> **username_3**: FWIW, we have very good parameters for the Moon's current orbit, primarily due to [LLR](https://en.wikipedia.org/wiki/Lunar_Laser_Ranging_experiment), but accurately calculating the lunar orbit via traditional analytical methods is [rather complicated](https://en.wikipedia.org/wiki/Lunar_theory). I have a basic 3D orbit plotter in Python using Horizons [here](https://astronomy.stackexchange.com/a/49823/16685).  

---

## 1 answers

### Answer by username_4 on 2022-10-02. Score: 2

From inspecting the JPL ephemeris website, the ephemeris with the longest time span as of this writing is DE441, which spans from August 15th, -13200 to March 15th, 17191. It is less accurate than DE440 (which covers the time span 1550-2650 AD), but is more stable over long time periods. For reference, between the years 1970-2020 the difference between DE441 and DE440 is less than 2 meters.
You can access this ephemeris using astropy. For example, I prepared the following script from astropy's tutorial, evaluating the Moon's position for Julian year -3000. The script will take a while to run the first time (since it needs to download the ephemeris), but subsequent runs will be much faster.
import numpy as np
import matplotlib.pyplot as plt
import astropy.units as u
import astropy.time
import astropy.coordinates
import astropy.visualization

astropy.visualization.quantity_support()
astropy.coordinates.solar_system_ephemeris.set('de441_part-1')

time_stop = astropy.time.Time('-3000', format='jyear')
time_start = time_stop - 27 * u.day
time = np.linspace(time_start, time_stop, num=1000)

location = astropy.coordinates.EarthLocation.from_geocentric(0 * u.m, 0 * u.m, 0 * u.m)

coords = astropy.coordinates.get_moon(time, location).cartesian

plt.figure(figsize=(9, 9))
plt.gca().set_aspect('equal')
plt.plot(coords.x, coords.y)
plt.scatter(coords[~0].x, coords[~0].y)
plt.savefig('moon.png')


---

