Index: trunk/psastro/src/psastroArguments.c
===================================================================
--- trunk/psastro/src/psastroArguments.c	(revision 26259)
+++ trunk/psastro/src/psastroArguments.c	(revision 35715)
@@ -74,4 +74,5 @@
 
     // apply mosastro mode?
+    bool mosastro = false;
     if ((N = psArgumentGet (argc, argv, "-mosastro"))) {
         psArgumentRemove (N, &argc, argv);
@@ -81,7 +82,9 @@
         psArgumentRemove (N, &argc, argv);
         psMetadataAddBool (config->arguments, PS_LIST_TAIL, "PSASTRO.MOSAIC.MODE", PS_META_REPLACE, "", true);
+        mosastro = true;
     }
 
     // apply chipastro mode?
+    bool chipastro = false;
     if ((N = psArgumentGet (argc, argv, "-chipastro"))) {
         psArgumentRemove (N, &argc, argv);
@@ -91,4 +94,18 @@
         psArgumentRemove (N, &argc, argv);
         psMetadataAddBool (config->arguments, PS_LIST_TAIL, "PSASTRO.CHIP.MODE", PS_META_REPLACE, "", true);
+        chipastro = true;
+    }
+    if ((N = psArgumentGet (argc, argv, "-skipastro"))) {
+        psArgumentRemove (N, &argc, argv);
+        if (mosastro) {
+            psError(PSASTRO_ERR_ARGUMENTS, true, "cannot specify +mosastro with -skipastro");
+            psErrorStackPrint(stderr, "exit");
+            return false;
+        }
+        if (chipastro) {
+            psError(PSASTRO_ERR_ARGUMENTS, true, "cannot specify +chipastro with -skipastro");
+            return false;
+        }
+        psMetadataAddBool (config->arguments, PS_LIST_TAIL, "PSASTRO.SKIP.ASTRO", PS_META_REPLACE, "", true);
     }