diff --git a/pygmtsar/pygmtsar/Stack_phasediff.py b/pygmtsar/pygmtsar/Stack_phasediff.py
index dd13daf4..76c132c6 100644
--- a/pygmtsar/pygmtsar/Stack_phasediff.py
+++ b/pygmtsar/pygmtsar/Stack_phasediff.py
@@ -94,7 +94,7 @@ def compute_interferogram_singlelook(self, pairs, name, weight=None, phase=None,
 
     # Goldstein filter requires square grid cells means 1:4 range multilooking.
     # For multilooking interferogram we can use square grid always using coarsen = (1,4)
-    def compute_interferogram_multilook(self, pairs, name, resolution=60., weight=None, phase=None,
+    def compute_interferogram_multilook(self, pairs, name, resolution=None, weight=None, phase=None,
                                         wavelength=None, psize=None, coarsen=(1,4), queue=16, debug=False):
         self.compute_interferogram(pairs, name, resolution=resolution, weight=weight, phase=phase,
                                    wavelength=wavelength, psize=psize, coarsen=coarsen, queue=queue, debug=debug)