Index: /trunk/psphot/src/psphotApResid.c
===================================================================
--- /trunk/psphot/src/psphotApResid.c	(revision 9832)
+++ /trunk/psphot/src/psphotApResid.c	(revision 9833)
@@ -25,4 +25,7 @@
     // S/N limit to perform full non-linear fits
     float MAX_AP_OFFSET = psMetadataLookupF32 (&status, recipe, "MAX_AP_OFFSET");
+
+    // this is the smallest radius allowed: need to at least extend growth curve down to this...
+    float PSF_FIT_PAD   = psMetadataLookupF32 (&status, recipe, "PSF_FIT_PADDING");
     bool  IGNORE_GROWTH = psMetadataLookupBool (&status, recipe, "IGNORE_GROWTH");
 
@@ -32,5 +35,5 @@
     // measure the aperture loss as a function of radius for PSF
     float REF_RADIUS = psMetadataLookupF32 (&status, recipe, "PSF_REF_RADIUS");
-    psf->growth = pmGrowthCurveAlloc (3.0, 100.0, REF_RADIUS);
+    psf->growth = pmGrowthCurveAlloc (PSF_FIT_PAD, 100.0, REF_RADIUS);
 
     psphotGrowthCurve (readout, psf, IGNORE_GROWTH);