fix trueAnomaly when r dot v < 0

jordanstephens · Jul 19, 2015 · 3fdbbf6 · 3fdbbf6
1 parent 18979ea
commit 3fdbbf6
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/lib/orbit.js b/lib/orbit.js
@@ -83,7 +83,8 @@ Orbit.prototype.argumentOfPeriapsis = function argumentOfPeriapsis() {
 
 Orbit.prototype.trueAnomaly = function trueAnomaly() {
   var e = this.eccentricity();
-  return toDeg(Math.acos(e.dot(this.r) / (e.norm() * this.r.norm())));
+  var u = toDeg(Math.acos(e.dot(this.r) / (e.norm() * this.r.norm())));
+  return this.r.dot(this.v) < 0 ? (360 - u) : u;
 };
 
 Orbit.prototype.periapsis = function periapsis() {