<p>The good software for orbit calculation is "Binary" (Binary Star Combined Solution Package) by CHARA team:</p>

<p><a href="http://www.astro.gsu.edu/~gudehus/binary.html" rel="nofollow">http://www.astro.gsu.edu/~gudehus/binary.html</a></p>

CC BY-SA 3.0
2014-11-11T20:42:34.353Z
The link is dead.
steveOw
CC BY-SA 3.0
2014-01-13T17:16:44.963Z
2015-05-08T19:35:24.850Z
2015-05-08T19:35:24.850Z
user2579566
<p>If it's a binary, it's fairly simple (in comparison with a ternary system), because the stars of the binary orbit about their common <a href="http://en.wikipedia.org/wiki/Barycentric_coordinates_%28astronomy%29" rel="nofollow">barycenter</a> in <a href="http://en.wikipedia.org/wiki/Kepler_orbit" rel="nofollow">Kepler ellipses</a>.</p>

<p>An orbit simulator, see <a href="http://astro.unl.edu/classaction/animations/renaissance/kepler.html" rel="nofollow">here</a>; replace the central star by the barycenter of the binaries.</p>

<p><a href="http://science.larouchepac.com/gauss/ceres/InterimII/Astronomy/KeplerProblem.html" rel="nofollow">Calculation of an Orbit from Three Observations</a>. <a href="http://en.wikipedia.org/wiki/Kepler_problem" rel="nofollow">Kepler problem on Wikipedia</a>.</p>

<p>If you don't find a ready-to-use software, try to solve it numerically by simulating the orbit of the binaries according to Kepler's law, and vary mass, distance, excentricity assumptions until they match to the observations. Use optimization methods, e.g. <a href="http://en.wikipedia.org/wiki/Hill_climbing" rel="nofollow">hill climbing algorithms</a>, or <a href="http://en.wikipedia.org/wiki/Gradient_method" rel="nofollow">gradient methods</a>.</p>

CC BY-SA 3.0
2014-01-09T03:23:42.150Z
Or, see for example: http://sourceforge.net/projects/phoebe/
Moriarty
CC BY-SA 3.0
2014-01-09T04:09:09.360Z
Needs some generalization to non-eclipsing binaries.
Gerald
CC BY-SA 3.0
2014-01-09T03:00:28.070Z
2014-01-09T03:00:28.070Z
Gerald
<p>I have a set of dates, position angles ($\theta$) and angular separations ($\rho$) for visual binary star. For example:</p>

<pre><code>1994.3132  57.0    0.097
1996.1783  73.4    0.051
2006.1938 182.0    0.126
2009.2597 192.9    0.152
etc.
</code></pre>

<p>What are algorithms to calculate orbital elements and to plot the orbit of the binary star?</p>

<p>Are there available codes (or programs) for this calculations?</p>

CC BY-SA 3.0
2015-05-08T14:30:00.327Z
The link has been changed to the following link: http://www.astro.gsu.edu/~gudehus/binary.html
user1527422
CC BY-SA 3.0
2014-01-08T22:46:57.473Z
Would http://scicomp.stackexchange.com/ be a better home for this question?
Qmechanic
<orbit><fundamental-astronomy><binary-star>
How to plot orbit of binary star and calculate its orbital elements?
user2579566
# How to plot orbit of binary star and calculate its orbital elements?

(Asked by: username_0 on 2014-01-08)

I have a set of dates, position angles ($\theta$) and angular separations ($\rho$) for visual binary star. For example:
1994.3132  57.0    0.097
1996.1783  73.4    0.051
2006.1938 182.0    0.126
2009.2597 192.9    0.152
etc.

What are algorithms to calculate orbital elements and to plot the orbit of the binary star?
Are there available codes (or programs) for this calculations?

**Tags:** orbit, fundamental-astronomy, binary-star
> **Comments:**
> **username_2**: Would http://scicomp.stackexchange.com/ be a better home for this question?  
> **username_1**: The link has been changed to the following link: http://www.astro.gsu.edu/~gudehus/binary.html  

---

## 2 answers

### Answer by username_0 on 2014-01-13. Score: 1 | Accepted answer

The good software for orbit calculation is "Binary" (Binary Star Combined Solution Package) by CHARA team:

<http://www.astro.gsu.edu/~gudehus/binary.html>

> **Comments:**
> **username_3**: The link is dead.  

---

### Answer by username_4 on 2014-01-09. Score: 3

If it's a binary, it's fairly simple (in comparison with a ternary system), because the stars of the binary orbit about their common [barycenter](http://en.wikipedia.org/wiki/Barycentric_coordinates_%28astronomy%29) in [Kepler ellipses](http://en.wikipedia.org/wiki/Kepler_orbit).

An orbit simulator, see [here](http://astro.unl.edu/classaction/animations/renaissance/kepler.html); replace the central star by the barycenter of the binaries.

[Calculation of an Orbit from Three Observations](http://science.larouchepac.com/gauss/ceres/InterimII/Astronomy/KeplerProblem.html). [Kepler problem on Wikipedia](http://en.wikipedia.org/wiki/Kepler_problem).

If you don't find a ready-to-use software, try to solve it numerically by simulating the orbit of the binaries according to Kepler's law, and vary mass, distance, excentricity assumptions until they match to the observations. Use optimization methods, e.g. [hill climbing algorithms](http://en.wikipedia.org/wiki/Hill_climbing), or [gradient methods](http://en.wikipedia.org/wiki/Gradient_method).

> **Comments:**
> **username_5**: Or, see for example: http://sourceforge.net/projects/phoebe/  
> **username_4**: Needs some generalization to non-eclipsing binaries.  

---

