Index: trunk/Mars/hawc/fresnellens_psf.C
===================================================================
--- trunk/Mars/hawc/fresnellens_psf.C	(revision 19785)
+++ trunk/Mars/hawc/fresnellens_psf.C	(revision 19786)
@@ -33,5 +33,8 @@
     double psf = 0;  // Do not change! It might have unpredicted side effectes
 
-    double angle = 6; // [cm] angle of incidence of simulates rays
+    double angle = 0; // [cm] angle of incidence of simulates rays
+
+    //TVector3 point_source(0, -F*atan(angle*TMath::DegToRad()), F);  // Point source at x=0, y=0, z=F
+    TVector3 point_source; // No point source
 
     MFresnelLens lens;
@@ -71,5 +74,13 @@
 
         TVector3 dir;
-        dir.SetMagThetaPhi(1, (180-angle)*TMath::DegToRad(), TMath::Pi()/2);
+        if (point_source.Mag()<1e-10)
+            dir.SetMagThetaPhi(1, (180-angle)*TMath::DegToRad(), TMath::Pi()/2);
+        else
+        {
+            // Note that this is not a perfect point source as the
+            // flux is homogeneous over the surface of the lens
+            TVector3 ps = pos - point_source;
+            dir.SetMagThetaPhi(1, ps.Theta(), ps.Phi());
+        }
 
         double v = 1./(TMath::C()*100/1e9); // cm/ns