diff --git a/rednose/helpers/sympy_helpers.py b/rednose/helpers/sympy_helpers.py
index 71a12d0..7f8813e 100644
--- a/rednose/helpers/sympy_helpers.py
+++ b/rednose/helpers/sympy_helpers.py
@@ -55,6 +55,7 @@ def euler2quat(eulers):
 def euler2rot(eulers):
   return quat2rot(euler2quat(eulers))
 
+
 rotations_from_quats = quat2rot
 
 
@@ -66,6 +67,13 @@ def cross(x):
   return ret
 
 
+def rot_to_euler(R):
+  gamma = sp.atan2(R[2, 1], R[2, 2])
+  theta = sp.asin(-R[2, 0])
+  psi = sp.atan2(R[1, 0], R[0, 0])
+  return sp.Matrix([gamma, theta, psi])
+
+
 def rot_matrix(roll, pitch, yaw):
   cr, sr = np.cos(roll), np.sin(roll)
   cp, sp = np.cos(pitch), np.sin(pitch)