Index: trunk/Ohana/src/opihi/include/astro.h
===================================================================
--- trunk/Ohana/src/opihi/include/astro.h	(revision 4689)
+++ trunk/Ohana/src/opihi/include/astro.h	(revision 16935)
@@ -11,3 +11,23 @@
 void InitAstro ();
 
+typedef struct {
+  int    isIdentity;	      // identity transformation 
+  double phi;		      // saved in radians
+  double Xo;		      // saved in radians
+  double xo;		      // saved in degrees
+  double sin_phi_cos_Xo;      // pre-computed values
+  double sin_phi_sin_Xo;      // pre-computed values
+  double cos_phi_cos_Xo;      // pre-computed values
+  double cos_phi_sin_Xo;      // pre-computed values
+  double cos_phi;	      // pre-computed values
+  double sin_phi;	      // pre-computed values
+  double cos_Xo;	      // pre-computed values
+  double sin_Xo;	      // pre-computed values
+} CoordTransform;
+
+typedef enum {COORD_NONE, COORD_CELESTIAL, COORD_GALACTIC, COORD_ECLIPTIC} CoordTransformSystem;
+
+CoordTransform *InitTransform (CoordTransformSystem input, CoordTransformSystem output);
+int ApplyTransform (double *x, double *y, double X, double Y, CoordTransform *transform);
+
 # endif