diff --git a/ObservationSim/sim_steps/add_LED_flat.py b/ObservationSim/sim_steps/add_LED_flat.py
index c1123ee570f7af6fa9fa6326ff04cc378bd3c68f..8946fdbb7892b213d4c5b3eb67e73a48210a3341 100644
--- a/ObservationSim/sim_steps/add_LED_flat.py
+++ b/ObservationSim/sim_steps/add_LED_flat.py
@@ -39,13 +39,13 @@ def add_LED_Flat(self, chip, filt, tel, pointing, catalog, obs_param):
     t_obs = Time(datetime_obs)
     
     ##ccd刷新2s,等待0.5s，开灯后等待0.5s,开始曝光
-    t_obs_renew = Time(t_obs.mjd - (2.+0.5 +0.5) / 86400., format="mjd")
+    t_obs_renew = Time(t_obs.mjd - (2.) / 86400., format="mjd")
 
     t_obs_utc = datetime.utcfromtimestamp(np.round(datetime.utcfromtimestamp(t_obs_renew.unix).replace(tzinfo=timezone.utc).timestamp(), 1))
     self.updateHeaderInfo(header_flag='prim', keys = ['DATE-OBS'], values = [t_obs_utc.strftime("%Y-%m-%dT%H:%M:%S.%f")[:-5]])
 
-    #dark time : 曝光时间+刷新后等带时间0.5s+点亮灯后0.5s+关闭快门时间1.5s+管快门后关灯前0.5+关灯后读出前等待0.5s
-    self.updateHeaderInfo(header_flag='ext', keys = ['DARKTIME'], values = [0.5+0.5+1.5+0.5+0.5+pointing.exp_time])
+    #dark time : 
+    self.updateHeaderInfo(header_flag='ext', keys = ['DARKTIME'], values = [pointing.exp_time])
 
     gc.collect()
     return chip, filt, tel, pointing
\ No newline at end of file
diff --git a/ObservationSim/sim_steps/add_objects.py b/ObservationSim/sim_steps/add_objects.py
index 26f61fef3058899bfac68b5670ff5a36535777fe..71a5e16710a0efe36693674e9ef8262e32e3767d 100644
--- a/ObservationSim/sim_steps/add_objects.py
+++ b/ObservationSim/sim_steps/add_objects.py
@@ -221,13 +221,13 @@ def add_objects(self, chip, filt, tel, pointing, catalog, obs_param):
     datetime_obs = datetime_obs.replace(tzinfo=timezone.utc)
     t_obs = Time(datetime_obs)
     
-    ##ccd刷新2s,等待0.5s，开始曝光
-    t_obs_renew = Time(t_obs.mjd - (2.+0.5) / 86400., format="mjd")
+    ##ccd刷新2s,等待0.s，开始曝光
+    t_obs_renew = Time(t_obs.mjd - (2.+0.) / 86400., format="mjd")
 
     t_obs_utc = datetime.utcfromtimestamp(np.round(datetime.utcfromtimestamp(t_obs_renew.unix).replace(tzinfo=timezone.utc).timestamp(), 1))
     self.updateHeaderInfo(header_flag='prim', keys = ['DATE-OBS'], values = [t_obs_utc.strftime("%Y-%m-%dT%H:%M:%S.%f")[:-5]])
 
-    #dark time : 曝光时间+刷新后等带时间0.5s+关闭快门时间1.5s+管快门后读出前等待0.5s
-    self.updateHeaderInfo(header_flag='ext', keys = ['DARKTIME'], values = [0.5+1.5+0.5+pointing.exp_time])
+    #dark time : 曝光时间+刷新后等带时间0.s+关快门后读出前等待0.s
+    self.updateHeaderInfo(header_flag='ext', keys = ['DARKTIME'], values = [0.+0.+pointing.exp_time])
 
     return chip, filt, tel, pointing
\ No newline at end of file