Index: trunk/ppTranslate/src/ppMopsWrite.c
===================================================================
--- trunk/ppTranslate/src/ppMopsWrite.c	(revision 32413)
+++ trunk/ppTranslate/src/ppMopsWrite.c	(revision 32415)
@@ -38,21 +38,29 @@
     psMetadataAddBool(header, PS_LIST_TAIL, "DIFF_POS", 0, "Positive subtraction?", args->positive);
 
-    // Get these header words from the first input
-    ppMopsDetections *det = detections->data[0];
-    psMetadataAddF64(header, PS_LIST_TAIL, "MJD-OBS", 0, "MJD of exposure midpoint", det->mjd);
-    psMetadataAddStr(header, PS_LIST_TAIL, "RA", 0, "Right Ascension of boresight", det->raBoresight);
-    psMetadataAddStr(header, PS_LIST_TAIL, "DEC", 0, "Declination of boresight", det->decBoresight);
-    psMetadataAddF64(header, PS_LIST_TAIL, "TEL_ALT", 0, "Telescope altitude", det->alt);
-    psMetadataAddF64(header, PS_LIST_TAIL, "TEL_AZ", 0, "Telescope azimuth", det->az);
-    psMetadataAddF64(header, PS_LIST_TAIL, "EXPTIME", 0, "Exposure time (sec)", det->exptime);
-    psMetadataAddF64(header, PS_LIST_TAIL, "ROTANGLE", 0, "Rotator position angle", det->posangle);
-    psMetadataAddStr(header, PS_LIST_TAIL, "FILTER", 0, "Filter name", det->filter);
-    psMetadataAddF32(header, PS_LIST_TAIL, "AIRMASS", 0, "Airmass of exposure", det->airmass);
+    // Get these header words from the first input non null input
+    ppMopsDetections *det = NULL;
+    for (int d = 0; d < detections->n && det == NULL; d++) {
+        det = detections->data[d];
+    }
+    if (det != NULL) {
+        psMetadataAddF64(header, PS_LIST_TAIL, "MJD-OBS", 0, "MJD of exposure midpoint", det->mjd);
+        psMetadataAddStr(header, PS_LIST_TAIL, "RA", 0, "Right Ascension of boresight", det->raBoresight);
+        psMetadataAddStr(header, PS_LIST_TAIL, "DEC", 0, "Declination of boresight", det->decBoresight);
+	psMetadataAddF64(header, PS_LIST_TAIL, "TEL_ALT", 0, "Telescope altitude", det->alt);
+	psMetadataAddF64(header, PS_LIST_TAIL, "TEL_AZ", 0, "Telescope azimuth", det->az);
+	psMetadataAddF64(header, PS_LIST_TAIL, "EXPTIME", 0, "Exposure time (sec)", det->exptime);
+	psMetadataAddF64(header, PS_LIST_TAIL, "ROTANGLE", 0, "Rotator position angle", det->posangle);
+	psMetadataAddStr(header, PS_LIST_TAIL, "FILTER", 0, "Filter name", det->filter);
+	psMetadataAddF32(header, PS_LIST_TAIL, "AIRMASS", 0, "Airmass of exposure", det->airmass);
+        psMetadataAddF32(header, PS_LIST_TAIL, "SEEING", 0, "Mean seeing", det->seeing);
+    } else {
+	psWarning("no inputs with surviving detections. output header will be incomplete");
+    }
     psMetadataAddStr(header, PS_LIST_TAIL, "OBSCODE", 0, "IAU Observatory code", OBSERVATORY_CODE);
-    psMetadataAddF32(header, PS_LIST_TAIL, "SEEING", 0, "Mean seeing", det->seeing);
     psMetadataAddF32(header, PS_LIST_TAIL, "MAGZP", 0, "Magnitude zero point", args->zp);
     psMetadataAddF32(header, PS_LIST_TAIL, "MAGZPERR", 0, "Error in magnitude zero point", args->zpErr);
     psMetadataAddF32(header, PS_LIST_TAIL, "ASTRORMS", 0, "RMS of astrometric fit", args->rmsAstrom);
-    //New field in header that tells about the CMF version
+
+    //field in header that tells about the CMF version
     char cmfVersion[8];
     sprintf(cmfVersion, PS1_DV_FORMAT, args->version);
@@ -102,5 +110,5 @@
         psMetadataAddF32(row, PS_LIST_TAIL, "RATIO_ALL", 0, "Ratio of positive pixels to all", NAN);
 
-	    if (args->version == 2) {
+	if (args->version == 2) {
 	      // Write data of version 2 (see ICD)
 	      psMetadataAdd (row, PS_LIST_TAIL, "IPP_IDET",         PS_DATA_U32, "IPP detection identifier index",
@@ -158,5 +166,5 @@
 	      psMetadataAdd (row, PS_LIST_TAIL, "PADDING",          PS_DATA_S16, "padding", 
 			     0);
-	    }
+	}
 
         if (!psFitsWriteTableEmpty(fits, header, row, OUT_EXTNAME)) {