<p>The available astrometric data for Mercury come from meridian transit timings (right ascension and declination) and radar or spacecraft ranging (distance).
NASA JPL has some
<a href="https://ssd.jpl.nasa.gov/?eph_data" rel="nofollow noreferrer">here</a>,
and the French IMCCE has some
<a href="http://www.geoazur.fr/astrogeo/?href=observations/base" rel="nofollow noreferrer">here</a>.
To use those, you'll have to work out some geometry including the position of Earth in its own orbit.</p>

<p>For your purpose it may be easier to use numerical ephemerides via
JPL <a href="https://ssd.jpl.nasa.gov/?ephemerides" rel="nofollow noreferrer">HORIZONS or SPICE</a>,
or IMCCE <a href="https://www.imcce.fr/services/ephemerides/" rel="nofollow noreferrer">Miriade or Multisat</a>,
which can output Cartesian coordinates if requested.
Of course these are fit to observational data themselves.
The underlying data files (e.g. DE430, INPOP17a) come with papers detailing sources, methods, uncertainties, etc.</p>

CC BY-SA 4.0
2019-03-16T03:59:28.517Z
The construction of the DE430 ephemeris and its data sources are described in [this JPL "memo"](https://ipnpr.jpl.nasa.gov/progress_report/42-196/196C.pdf) in Table 1. Mercury data is roughly 50/50 ranges to _Messenger_ and radar ranges
astrosnapper
CC BY-SA 4.0
2019-03-16T02:29:24.353Z
2019-03-16T21:36:13.473Z
2019-03-16T21:36:13.473Z
Mike G
<p>I have a project in which a Monte-Carlo method is used to find the optimal parameters for some model that is fit to a data set. I want to fit a model for the orbit of Mercury using this methods, but I can't find any data to fit it to. I have found a lot of papers on the orbit of Mercury that mention observational data, but no actual observational data. Where could I find data indicating the position of Mercury around the sun over a time period, or even a relatively accurate mathematical model from which I can generate my own data by defining it as a function that is stepped through some time interval?</p>

CC BY-SA 4.0
2019-03-16T00:17:11.893Z
This is a great question! There is already a [similar question with a great answer](https://astronomy.stackexchange.com/q/13488/7982) and I think you question will be closed as duplicate to it. Don't worry, that happens to all of us, it's just Stack Exchange's way of directing future readers who land on a a question to be directed towards high value answers.
uhoh
CC BY-SA 4.0
2019-03-16T00:21:24.393Z
I would personally recommend either the gold standard of JPL's spice package, or JPL's [Horizons](https://ssd.jpl.nasa.gov/horizons.cgi) web interface (here's a [how-to](https://space.stackexchange.com/a/25357/12102))  to it (like I used [in this answer including several perturbations important for Mercury](https://space.stackexchange.com/a/23409/12102)) or the *most convenient solution*; the Python package [Skyfield](https://rhodesmill.org/skyfield/).
uhoh
CC BY-SA 4.0
2019-03-16T01:12:29.053Z
by the way [this question](https://space.stackexchange.com/q/34821/12102) could probably be answered using a Monte-Carlo orbit solution as well; seems like it would be fun!
uhoh
<observational-astronomy><data-analysis><orbital-elements><mercury><raw-data>
Where can I find data on Mercury's orbit to fit a model to?
DeNLau
# Where can I find data on Mercury's orbit to fit a model to?

(Asked by: username_0 on 2019-03-15)

I have a project in which a Monte-Carlo method is used to find the optimal parameters for some model that is fit to a data set. I want to fit a model for the orbit of Mercury using this methods, but I can't find any data to fit it to. I have found a lot of papers on the orbit of Mercury that mention observational data, but no actual observational data. Where could I find data indicating the position of Mercury around the sun over a time period, or even a relatively accurate mathematical model from which I can generate my own data by defining it as a function that is stepped through some time interval?

**Tags:** observational-astronomy, data-analysis, orbital-elements, mercury, raw-data

> **Comments:**
> **username_1**: This is a great question! There is already a [similar question with a great answer](https://astronomy.stackexchange.com/q/13488/7982) and I think you question will be closed as duplicate to it. Don't worry, that happens to all of us, it's just Stack Exchange's way of directing future readers who land on a a question to be directed towards high value answers.  
> **username_1**: I would personally recommend either the gold standard of JPL's spice package, or JPL's [Horizons](https://ssd.jpl.nasa.gov/horizons.cgi) web interface (here's a [how-to](https://space.stackexchange.com/a/25357/12102))  to it (like I used [in this answer including several perturbations important for Mercury](https://space.stackexchange.com/a/23409/12102)) or the *most convenient solution*; the Python package [Skyfield](https://rhodesmill.org/skyfield/).  
> **username_1**: by the way [this question](https://space.stackexchange.com/q/34821/12102) could probably be answered using a Monte-Carlo orbit solution as well; seems like it would be fun!  

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## 1 answers

### Answer by username_2 on 2019-03-16. Score: 0

The available astrometric data for Mercury come from meridian transit timings (right ascension and declination) and radar or spacecraft ranging (distance).
NASA JPL has some
[here](https://ssd.jpl.nasa.gov/?eph_data),
and the French IMCCE has some
[here](http://www.geoazur.fr/astrogeo/?href=observations/base).
To use those, you'll have to work out some geometry including the position of Earth in its own orbit.

For your purpose it may be easier to use numerical ephemerides via
JPL [HORIZONS or SPICE](https://ssd.jpl.nasa.gov/?ephemerides),
or IMCCE [Miriade or Multisat](https://www.imcce.fr/services/ephemerides/),
which can output Cartesian coordinates if requested.
Of course these are fit to observational data themselves.
The underlying data files (e.g. DE430, INPOP17a) come with papers detailing sources, methods, uncertainties, etc.

> **Comments:**
> **username_3**: The construction of the DE430 ephemeris and its data sources are described in [this JPL "memo"](https://ipnpr.jpl.nasa.gov/progress_report/42-196/196C.pdf) in Table 1. Mercury data is roughly 50/50 ranges to _Messenger_ and radar ranges  

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