Index: trunk/psastro/src/psastroMaskUtils.c
===================================================================
--- trunk/psastro/src/psastroMaskUtils.c	(revision 24045)
+++ trunk/psastro/src/psastroMaskUtils.c	(revision 33851)
@@ -135,5 +135,5 @@
 	// XXX optimize this
 	float A = 1.0;
-	float B = shape.sxy*y*PS_SQR(shape.sx);
+	float B = 2.0 * shape.sxy*y*PS_SQR(shape.sx);
 	float C = PS_SQR(y*shape.sx/shape.sy) - PS_SQR(shape.sx);