Initial commit

1 files changed, 33 insertions, 0 deletions

diff --git a/vo/votools/gasplib/treqst.x b/vo/votools/gasplib/treqst.x
new file mode 100644
index 00000000..9e6b6548
--- /dev/null
+++ b/vo/votools/gasplib/treqst.x
@@ -0,0 +1,33 @@
+define	ARCSEC_PER_RADIAN	206264.8062470964d0
+# TREQST -- Procedure to convert RA and Dec to standard coordinates
+#	    given the plate centre.
+
+procedure  treqst (plate_centre_ra, plate_centre_dec,
+     		   object_ra, object_dec, xi_object, eta_object)
+
+double		plate_centre_ra	      #i: (radians)	
+double		plate_centre_dec      #i: (radians)	
+double		object_ra             #i: (radians)
+double		object_dec            #i: (radians)		
+double		xi_object	      #o: standard coordinate (rad)
+double		eta_object	      #o: standard coordinate (rad)	
+
+double		div	
+
+begin
+	# Find divisor
+	div=(dsin(object_dec)*dsin(plate_centre_dec)+
+     	     dcos(object_dec)*dcos(plate_centre_dec)*
+     	     dcos(object_ra-plate_centre_ra))
+
+	# Compute standard coords and convert to arcsec
+
+	xi_object = dcos(object_dec)*dsin(object_ra-plate_centre_ra)*
+     		  ARCSEC_PER_RADIAN/div
+
+	eta_object = (dsin(object_dec)*dcos(plate_centre_dec)-
+     		    dcos(object_dec)*dsin(plate_centre_dec)*
+     		    dcos(object_ra-plate_centre_ra))*
+     		    ARCSEC_PER_RADIAN/div
+
+end