add straylight limit for big value

        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