Avoid division by zero error in ObservationStats class
@@ -73,6 +73,8 @@ class ObservationStats(Stats):
obs_id = obs.obs_id
livetime = obs.observation_live_time_duration
+ alpha = 0
+ if a_off > 0:
alpha = a_on / a_off
gamma_rate = n_on / livetime.to(u.min)
