Index: /trunk/Ohana/src/opihi/cmd.astro/coord_systems.c
===================================================================
--- /trunk/Ohana/src/opihi/cmd.astro/coord_systems.c	(revision 30657)
+++ /trunk/Ohana/src/opihi/cmd.astro/coord_systems.c	(revision 30658)
@@ -21,7 +21,30 @@
 	  break;
 	case COORD_GALACTIC:
-	  transform->phi = -62.60*RAD_DEG;
-	  transform->Xo  = 282.25*RAD_DEG;
-	  transform->xo  =  33.00;
+
+	  // J2000 FK5 transformation from Liu et al 2011 (A&A 526, A16)
+	  transform->phi = -62.8717488056*RAD_DEG;
+	  transform->Xo  = 282.8594812080*RAD_DEG;
+	  transform->xo  =  32.9319185700;
+
+	  // these are derived from their eqn (10):
+	  // \alpha^p_J =  12h 51m 26.27549s
+	  // \delta^p_J = +27d 07' 41.7043"
+	  // \theta_J   = 122.93191857 deg
+	  // phi = -90 - \alpha^p_J
+	  // Xo  = +90 - \delta^p_J
+	  // xo  = \theta_J - 90
+
+	  // Liu et al also propose an alternative ICRS definition using:
+	  // \alpha^p_J =  12h 51m 26.27469s
+	  // \delta^p_J = +27d 07' 41.7087"
+	  // \theta_J   = 122.93192526 deg
+	  // these differ from the above at the several milliarcsec level
+
+
+	  // These values were used in the past, but transform to/from B1950.0
+	  // transform->phi = -62.60*RAD_DEG;
+	  // transform->Xo  = 282.25*RAD_DEG;
+	  // transform->xo  =  33.00;
+
 	  break;
 	case COORD_ECLIPTIC:
@@ -63,7 +86,13 @@
       switch (output) {
 	case COORD_CELESTIAL:
-	  transform->phi =  62.60*RAD_DEG;
-	  transform->Xo  =  33.00*RAD_DEG;
-	  transform->xo  = 282.25;
+	  // J2000 transformation from Liu et al 2011 ()
+	  transform->phi =  62.8717488056*RAD_DEG;
+	  transform->Xo  =  32.9319185700*RAD_DEG;
+	  transform->xo  = 282.8594812080;
+
+	  // These values were used in the past, but transform to/from B1950.0
+	  // transform->phi =  62.60*RAD_DEG;
+	  // transform->Xo  =  33.00*RAD_DEG;
+	  // transform->xo  = 282.25;
 	  break;
 	case COORD_GALACTIC: