diff --git a/cost_function.py b/cost_function.py
index 024e5182d7709d6c85c2fc60747e4f84726b087c..b8a349893e062d8e753cfd807da453de8b7aa2e7 100755
--- a/cost_function.py
+++ b/cost_function.py
@@ -34,7 +34,7 @@ def calculate_radii_rossby(list_eddies, e_overestim, handlers, array_d_init):
     radii = 0 # in m
     rossby = 0
     days_modifier = 0
-    Omega = 2 * math.pi / 86400.
+    Omega = 2 * math.pi / 86164.
 
     for n in list_eddies:
         current_eddy = report_graph.node_to_date_eddy(n, e_overestim)