Index: /trunk/psModules/src/camera/pmFPAMosaic.c
===================================================================
--- /trunk/psModules/src/camera/pmFPAMosaic.c	(revision 13338)
+++ /trunk/psModules/src/camera/pmFPAMosaic.c	(revision 13339)
@@ -428,5 +428,6 @@
                             const psVector *yBinSource, // Binning in y of source images
                             int xBinTarget, int yBinTarget, // Binning in x and y of target images
-                            const psVector *x0, const psVector *y0 // Offsets for source images on target
+                            const psVector *x0, const psVector *y0, // Offsets for source images on target
+                            double unexposed // Value for unexposed pixels
                            )
 {
@@ -802,7 +803,7 @@
     // Mosaic the images together and we're done
     if (allGood) {
-        *mosaicImage = imageMosaic(images, xFlip, yFlip, xBin, yBin, *xBinChip, *yBinChip, x0, y0);
-        *mosaicWeights = imageMosaic(weights, xFlip, yFlip, xBin, yBin, *xBinChip, *yBinChip, x0, y0);
-        *mosaicMask = imageMosaic(masks, xFlip, yFlip, xBin, yBin, *xBinChip, *yBinChip, x0, y0);
+        *mosaicImage = imageMosaic(images, xFlip, yFlip, xBin, yBin, *xBinChip, *yBinChip, x0, y0, NAN);
+        *mosaicWeights = imageMosaic(weights, xFlip, yFlip, xBin, yBin, *xBinChip, *yBinChip, x0, y0, NAN);
+        *mosaicMask = imageMosaic(masks, xFlip, yFlip, xBin, yBin, *xBinChip, *yBinChip, x0, y0, 0xff);
     }
 
@@ -935,7 +936,7 @@
     // Mosaic the images together and we're done
     if (allGood) {
-        *mosaicImage = imageMosaic(images, xFlip, yFlip, xBin, yBin, *xBinFPA, *yBinFPA, x0, y0);
-        *mosaicWeights = imageMosaic(weights, xFlip, yFlip, xBin, yBin, *xBinFPA, *yBinFPA, x0, y0);
-        *mosaicMask = imageMosaic(masks, xFlip, yFlip, xBin, yBin, *xBinFPA, *yBinFPA, x0, y0);
+        *mosaicImage = imageMosaic(images, xFlip, yFlip, xBin, yBin, *xBinFPA, *yBinFPA, x0, y0, NAN);
+        *mosaicWeights = imageMosaic(weights, xFlip, yFlip, xBin, yBin, *xBinFPA, *yBinFPA, x0, y0, NAN);
+        *mosaicMask = imageMosaic(masks, xFlip, yFlip, xBin, yBin, *xBinFPA, *yBinFPA, x0, y0, 0xff);
     }
 
@@ -1105,16 +1106,27 @@
 
     // If the cells contain the headers, we need to apply the WCS terms from (one of?) the cells
-    int xParityTarget = psMetadataLookupS32(NULL, target->concepts, "CHIP.XPARITY") *
-        psMetadataLookupS32(NULL, targetCell->concepts, "CELL.XPARITY"); // Target parity in x
-    if (xParityTarget != -1 && xParityTarget != 1) {
-        psError(PS_ERR_BAD_PARAMETER_VALUE, true, "CHIP.XPARITY or CELL.XPARITY is not set for target.");
-        return false;
-    }
-    int yParityTarget = psMetadataLookupS32(NULL, target->concepts, "CHIP.YPARITY") *
-        psMetadataLookupS32(NULL, targetCell->concepts, "CELL.YPARITY"); // Target parity in y
-    if (yParityTarget != -1 && yParityTarget != 1) {
-        psError(PS_ERR_BAD_PARAMETER_VALUE, true, "CHIP.YPARITY or CELL.YPARITY is not set for target.");
-        return false;
-    }
+    int xParityCellTarget = psMetadataLookupS32(NULL, targetCell->concepts, "CELL.XPARITY");
+    if (xParityCellTarget != -1 && xParityCellTarget != 1) {
+        psError(PS_ERR_BAD_PARAMETER_VALUE, true, "CELL.XPARITY is not set for target.");
+        return false;
+    }
+    int xParityChipTarget = psMetadataLookupS32(NULL, target->concepts, "CHIP.XPARITY");
+    if (xParityChipTarget != -1 && xParityChipTarget != 1) {
+        psError(PS_ERR_BAD_PARAMETER_VALUE, true, "CHIP.XPARITY is not set for target.");
+        return false;
+    }
+    int xParityTarget = xParityCellTarget * xParityChipTarget; // Target parity in x
+
+    int yParityCellTarget = psMetadataLookupS32(NULL, targetCell->concepts, "CELL.YPARITY");
+    if (yParityCellTarget != -1 && yParityCellTarget != 1) {
+        psError(PS_ERR_BAD_PARAMETER_VALUE, true, "CELL.YPARITY is not set for target.");
+        return false;
+    }
+    int yParityChipTarget = psMetadataLookupS32(NULL, target->concepts, "CHIP.YPARITY");
+    if (yParityChipTarget != -1 && yParityChipTarget != 1) {
+        psError(PS_ERR_BAD_PARAMETER_VALUE, true, "CHIP.YPARITY is not set for target.");
+        return false;
+    }
+    int yParityTarget = yParityCellTarget * yParityChipTarget; // Target parity in y
 
     for (int i = 0; i < source->cells->n; i++) {