diff --git a/src/orbits.cpp b/src/orbits.cpp
index ba5df23..3ab9303 100644
--- a/src/orbits.cpp
+++ b/src/orbits.cpp
@@ -38,8 +38,8 @@ ellipseInitAB(double a, double b)
 	ep.c = sqrt(a * a - b * b);
 	ep.e = ep.c / ep.a;
 	ep.p = ep.a * (1 - pow(ep.e, 2));
-	ep.f1.x = -1 * ep.c;
-	ep.f2.x = ep.c;
+	ep.f1.x = ep.c;
+	ep.f2.x = -1 * ep.c;
 	return ep;
 }
 
diff --git a/src/orbits.h b/src/orbits.h
index b6e60ac..6410068 100644
--- a/src/orbits.h
+++ b/src/orbits.h
@@ -15,9 +15,8 @@ struct ellipse_parameters
 	double e;	// NOTE: eccentricity
 	double c;	// NOTE: linear eccentricity
 	double p;	// NOTE: semilatus rectum
-	// FIXME: these should be swapped so f1 is primary focus
-	glm::vec2 f1;	// NOTE: 'vacant' focus
-	glm::vec2 f2;	// NOTE: 'primary' focus
+	glm::vec2 f1;	// NOTE: 'primary' focus
+	glm::vec2 f2;	// NOTE: 'vacant' focus
 };
 
 struct orbital_elements