diff --git a/python/obitools3/uri/decode.pyx b/python/obitools3/uri/decode.pyx
old mode 100644
new mode 100755
index 0e5df55..74d44d7
--- a/python/obitools3/uri/decode.pyx
+++ b/python/obitools3/uri/decode.pyx
@@ -162,7 +162,8 @@ Reads an URI and returns a tuple containing:
 '''
 def open_uri(uri,
              bint input=True,
-             type newviewtype=View):
+             type newviewtype=View,
+             dms_only=False):
     
     cdef bytes urib = tobytes(uri)
     cdef bytes scheme
@@ -200,6 +201,11 @@ def open_uri(uri,
             dms=(default_dms, urip.path)
 
         if dms is not None:
+            if dms_only:
+                return (dms[0],
+                        dms[1],
+                        type(dms[1]),
+                        urlunparse(urip))
             try:
                 resource=open_dms_element(dms[0],
                                           dms[1],
@@ -229,7 +235,7 @@ def open_uri(uri,
                    
     if scheme==b"dms" :
         logger('Error','Could not open DMS URI: %s', uri)
-        raise FileNotFoundError('uri')
+        raise FileNotFoundError()
 
     if not urip.scheme:
         urib=b"file:"+urib