diff --git a/miscmaths.h b/miscmaths.h
index f32b983c6aa102874a1fa8531a748b2a42732892..7c28d54c386e8c8f376b5c9bda5761fcbceeddb5 100644
--- a/miscmaths.h
+++ b/miscmaths.h
@@ -165,6 +165,7 @@ namespace MISCMATHS {
   
   void cart2sph(const ColumnVector& dir, float& th, float& ph);// cartesian to sperical polar coordinates
   void cart2sph(const Matrix& dir,ColumnVector& th,ColumnVector& ph);//ditto
+  void cart2sph(const vector<ColumnVector>& dir,ColumnVector& th,ColumnVector& ph);// same but in a vector
 
   // returns the first P such that 2^P >= abs(N). 
   int nextpow2(int n);