Index: trunk/ppSub/src/ppSubReadoutPhotometry.c
===================================================================
--- trunk/ppSub/src/ppSubReadoutPhotometry.c	(revision 32822)
+++ trunk/ppSub/src/ppSubReadoutPhotometry.c	(revision 37966)
@@ -46,4 +46,9 @@
         psFree(view);
         return false;
+    }
+
+    // psphot may need the PHU header
+    if (!photFile->fpa->hdu) {
+      photFile->fpa->hdu = psMemIncrRefCounter (inFile->fpa->hdu);
     }