diff --git a/src/nuspacesim/simulation/eas_optical/eas.py b/src/nuspacesim/simulation/eas_optical/eas.py
index 7e0ff83..31fad37 100644
--- a/src/nuspacesim/simulation/eas_optical/eas.py
+++ b/src/nuspacesim/simulation/eas_optical/eas.py
@@ -65,7 +65,7 @@ def altDec(self, beta, tauBeta, tauLorentz, u=None, *args, **kwargs):
 
         tDec = -tauLorentz * mean_Tau_life * np.log(u)  # seconds
 
-        lenDec = 1000.0 * tDec * tauBeta * c.value  # km
+        lenDec = 1e-3 * tDec * tauBeta * c.value  # km
 
         altDec = np.sqrt(
             R_earth.to(units.km).value ** 2