<p>Buy <em>Astronomical Algorithms</em> 2nd ed. by Jean Meeus. It is published by Willmann-Bell Inc. If you buy it direct from the publisher, you will get a corrected printing with all errata up to August 10, 2009. There are a number of systems for describing the location of a planet. This book provides a method to find the heliocentric longitude, latitude, and distance from the Sun. It also explains the different coordinate systems and how to transform from one to another.</p>

<p>The method you use depends on how accurate you need to be. If you state your needed accuracy some of us might be able to suggest other alternatives. </p>

CC BY-SA 3.0
2015-07-12T15:35:59.043Z
Can you describe the relevant information?
HDE 226868
CC BY-SA 3.0
2015-07-13T16:58:23.953Z
The book has 58 pages of coefficients, and an explanation of how to combine the coefficients to find the positions. There are other sources that are shorter but less accurate, or (much) longer but less accurate.
Gerard Ashton
CC BY-SA 3.0
2015-07-12T15:28:43.673Z
2015-07-12T15:28:43.673Z
Gerard Ashton
<p>(DISCLAIMER) I am not an expert on this subject, and I only hope that my answer will attract better, and more complete ones.</p>

<p>The Meeus book that @Gerard Ashton mentioned is a great resource for amateurs, but I am worried whether it is accurate enough for, let's say, eclipse or transit predictions. Also I glanced at the site linked in the question and saw something like "A live view of Plutonian system". To be honest I don't think that the Meeus book can enable you to do that kind of thing.</p>

<p>As far as I know, serious calculations of planetary positions are done today with the help of dynamical ephemerides developed and maintained by specialized agencies, such as <a href="https://en.wikipedia.org/wiki/VSOP_(planets)" rel="nofollow">VSOP87</a> by the Bureau des Longitudes in France, and <a href="https://en.wikipedia.org/wiki/Jet_Propulsion_Laboratory_Development_Ephemeris" rel="nofollow">DE431</a> by Jet propulsion laboratory of NASA. The NASA <a href="http://ssd.jpl.nasa.gov/?horizons" rel="nofollow">Horizons</a> system is an online interface from which you can get the planets' positions. (It's powered by some version of the DE ephemeris, I think.) It is well documented, so feel free to check out their <a href="http://ssd.jpl.nasa.gov/?horizons_doc" rel="nofollow">documentation</a> if you want to have a go.</p>

CC BY-SA 3.0
2016-12-09T22:36:51.540Z
Meeus used a truncated version of VSOP87... Explanation on its usage is here: https://www.caglow.com/info/compute/vsop87   ...  Also, there is a source code generator for it (C/C++, Java, PHP, Basic, VB.Net) : http://neoprogrammics.com/vsop87/source_code_generator_tool/  Current version is VSOP2013... Personally I am using VSOP2000 because it is the only one has the moon positions...
Huy Pham
CC BY-SA 3.0
2016-02-08T13:51:06.623Z
2016-02-08T13:51:06.623Z
Kaius
<p>I'm making an application that needs to calculate a planet's current position within the solar system - I don't want to calculate its position in the sky.</p>

<p>For example, what I want to do is exactly what this website does:</p>

<p><a href="http://www.theplanetstoday.com/" rel="nofollow">http://www.theplanetstoday.com/</a></p>

<p>I want to create an overhead view of all the planet's positions in the solar system.</p>

<p>Where do I start? Is there a latitude/longitude coordinate system for the solar system? Everything I've found seems to calculate a planet's position in the sky from the observer's point on earth.</p>

CC BY-SA 3.0
2015-07-14T02:28:57.120Z
Thanks barry, this is exactly what I needed. By using the vector ephemeris type HORIZONS calculates the x, y, and z coordinates of planetary bodies relative to the sun. If I need to dig deeper into it I'll use Gerard's answer, but for now this should do.
Bilbo Baggins
<solar-system><planet>
How to calculate a planet's current position within the solar system
Bilbo Baggins
# How to calculate a planet's current position within the solar system

(Asked by: username_0 on 2015-07-11)

I'm making an application that needs to calculate a planet's current position within the solar system - I don't want to calculate its position in the sky.

For example, what I want to do is exactly what this website does:

<http://www.theplanetstoday.com/>

I want to create an overhead view of all the planet's positions in the solar system.

Where do I start? Is there a latitude/longitude coordinate system for the solar system? Everything I've found seems to calculate a planet's position in the sky from the observer's point on earth.

**Tags:** solar-system, planet
> **Comments:**
> **username_0**: Thanks barry, this is exactly what I needed. By using the vector ephemeris type HORIZONS calculates the x, y, and z coordinates of planetary bodies relative to the sun. If I need to dig deeper into it I'll use Gerard's answer, but for now this should do.  

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## 2 answers

### Answer by username_1 on 2015-07-12. Score: 2 | Accepted answer

Buy *Astronomical Algorithms* 2nd ed. by Jean Meeus. It is published by Willmann-Bell Inc. If you buy it direct from the publisher, you will get a corrected printing with all errata up to August 10, 2009. There are a number of systems for describing the location of a planet. This book provides a method to find the heliocentric longitude, latitude, and distance from the Sun. It also explains the different coordinate systems and how to transform from one to another.

The method you use depends on how accurate you need to be. If you state your needed accuracy some of us might be able to suggest other alternatives.

> **Comments:**
> **username_2**: Can you describe the relevant information?  
> **username_1**: The book has 58 pages of coefficients, and an explanation of how to combine the coefficients to find the positions. There are other sources that are shorter but less accurate, or (much) longer but less accurate.  

---

### Answer by username_3 on 2016-02-08. Score: 1

(DISCLAIMER) I am not an expert on this subject, and I only hope that my answer will attract better, and more complete ones.

The Meeus book that @Gerard Ashton mentioned is a great resource for amateurs, but I am worried whether it is accurate enough for, let's say, eclipse or transit predictions. Also I glanced at the site linked in the question and saw something like "A live view of Plutonian system". To be honest I don't think that the Meeus book can enable you to do that kind of thing.

As far as I know, serious calculations of planetary positions are done today with the help of dynamical ephemerides developed and maintained by specialized agencies, such as [VSOP87](https://en.wikipedia.org/wiki/VSOP_(planets)) by the Bureau des Longitudes in France, and [DE431](https://en.wikipedia.org/wiki/Jet_Propulsion_Laboratory_Development_Ephemeris) by Jet propulsion laboratory of NASA. The NASA [Horizons](http://ssd.jpl.nasa.gov/?horizons) system is an online interface from which you can get the planets' positions. (It's powered by some version of the DE ephemeris, I think.) It is well documented, so feel free to check out their [documentation](http://ssd.jpl.nasa.gov/?horizons_doc) if you want to have a go.

> **Comments:**
> **username_4**: Meeus used a truncated version of VSOP87... Explanation on its usage is here: https://www.caglow.com/info/compute/vsop87   ...  Also, there is a source code generator for it (C/C++, Java, PHP, Basic, VB.Net) : http://neoprogrammics.com/vsop87/source_code_generator_tool/  Current version is VSOP2013... Personally I am using VSOP2000 because it is the only one has the moon positions...  

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