Index: trunk/ppSim/src/ppSimMakeGalaxies.c
===================================================================
--- trunk/ppSim/src/ppSimMakeGalaxies.c	(revision 36079)
+++ trunk/ppSim/src/ppSimMakeGalaxies.c	(revision 41173)
@@ -45,9 +45,10 @@
     float zp       	  = psMetadataLookupF32(&mdok, recipe, "ZEROPOINT"); // Photometric zero point
     float seeing   	  = psMetadataLookupF32(&mdok, recipe, "SEEING"); // Seeing sigma (pix)
-    float scale    	  = psMetadataLookupF32(&mdok, recipe, "PIXEL.SCALE") * M_PI / 3600.0 / 180.0; // Plate scale (radians/pixel)
+    float scale    	  = psMetadataLookupF32(&mdok, recipe, "PIXEL.SCALE"); // Plate scale (arcsec/pixel)
     float skyRate  	  = psMetadataLookupF32(&mdok, recipe, "SKY.RATE"); // Sky rate
     if (isnan(skyRate)) {
 	float skyMags = psMetadataLookupF32(&mdok, recipe, "SKY.MAGS");  assert (mdok);
 	skyRate = scale * scale * ppSimMagToFlux (skyMags, zp);
+	// skyMags is in mags / square arcsec so scale must be arcsec / pixel
     }
 
@@ -94,5 +95,5 @@
 
     // Normalisation, set by the specified stellar density at the specified bright magnitude
-    float refSum = galaxyDensity * xSize * ySize * PS_SQR(scale * 180.0 / M_PI);
+    float refSum = galaxyDensity * xSize * ySize * PS_SQR(scale / 3600.0);
     float normLum =  refSum / (galaxyAlpha * logf(10.0) * powf(10.0, (galaxyAlpha * brightMag)));
     float normScale = normLum * galaxyAlpha * logf(10.0);
@@ -143,5 +144,4 @@
 		rndValue = galaxyGridRandom ? drand48() : i / (float) nTotal;
 		float scale = (galaxyRmajorMin + rndValue * galaxyRmajorSlope);
-
 		galaxy->Rmaj  = scale;