issue29,sky dark time

ObservationSim/sim_steps/add_sky_background.py

@@ -136,7 +136,7 @@ def add_sky_background(self, chip, filt, tel, pointing, catalog, obs_param):
     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])
+    self.updateHeaderInfo(header_flag='ext', keys = ['DARKTIME'], values = [0.+0.0+0.0+pointing.exp_time])
 
 
     return chip, filt, tel, pointing
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