Index: /branches/eam_branches/ipp-20130904/psModules/src/objects/models/pmModel_EXP.c
===================================================================
--- /branches/eam_branches/ipp-20130904/psModules/src/objects/models/pmModel_EXP.c	(revision 36244)
+++ /branches/eam_branches/ipp-20130904/psModules/src/objects/models/pmModel_EXP.c	(revision 36245)
@@ -63,4 +63,17 @@
 // 0.5 PIX: the parameters are defined in terms of pixel coords, so the incoming pixcoords
 // values need to be pixel coords
+//
+
+// Notes on changing kappa value from 1.70056 to 1.678
+// I'm using a functional form f(x,y) = Io exp(-kappa (r / r_e)).  
+// The article by Graham & Driver (2005) uses a form Ie exp(-bn [(r / r_e) -1]) 
+// which is equal to Ie exp(-bn (r / r_e)) exp(bn).  
+// Thus, my Io = Ie exp(bn) and my kappa is their bn.
+// My value of kappa is 1.700, their value for bn is 1.678., so I am off by a small amount there (1.5%).  
+
+
+#define KAPPA_EXP 1.678
+#define OLD_KAPP_EXP 1.70056
+
 
 // Lax parameter limits
@@ -109,5 +122,5 @@
     // for EXP, we can hard-wire kappa(1):
     // float index = 1.0;
-    float kappa = 1.70056;
+    float kappa = KAPPA_EXP;
 
     // sqrt(z) is r
@@ -318,5 +331,5 @@
 
     // static value for EXP:
-    float kappa = 1.70056;
+    float kappa = KAPPA_EXP;
 
     // f = Io exp(-kappa*sqrt(z)) -> sqrt(z) = ln(Io/f) / kappa