add straylight limit for big value

ObservationSim/Instrument/Filter.py

@@ -115,10 +115,14 @@ class Filter(object):
         sl = Straylight(jtime=jtime, sat_pos=sat_pos, pointing_radec=pointing_radec,sun_pos=sun_pos)
         if self.filter_type in ["GU","GV","GI"]:
             s_pix, spec = sl.calculateStrayLightGrating(grating = self.filter_type.upper())
+            if s_pix>0.8:
+                s_pix = 0.8
             self.sky_background = s_pix
             self.zodical_spec = spec
         elif self.filter_type.lower() in ["nuv","u","g","r","i","z","y"]:
             s_pix = sl.calculateStrayLightFilter(filter=self.filter_type.lower())
+            if s_pix>1:
+                s_pix = 1
             self.sky_background = s_pix
             self.zodical_spec = None