Index: /trunk/dvoTools/src/dvoMakeCorrLoop.c
===================================================================
--- /trunk/dvoTools/src/dvoMakeCorrLoop.c	(revision 41679)
+++ /trunk/dvoTools/src/dvoMakeCorrLoop.c	(revision 41680)
@@ -61,5 +61,9 @@
 	assert (inChip->hdu);
 	assert (inChip->hdu->extname);
-	psFitsMoveExtName (input->fits, inChip->hdu->extname);
+
+	// not all extensions are required to exist.  skip if not found
+	if (!psFitsMoveExtName (input->fits, inChip->hdu->extname)) {
+	  continue;
+	}
 	psImage *inImage = psFitsReadImage (input->fits, fullImage, 0);
 	assert (inImage);