;$Id:$
   ;-------------------------------------------------
   ; make a structure to hold data and attributes
   ;-------------------------------------------------
   table = {single : fltarr(attributes.nbins_x,attributes.nbins_y), $
            overlap: fltarr(attributes.nbins_x,attributes.nbins_y), $
            obs : fltarr(attributes.nbins_x,attributes.nbins_y), $
            single_fraction : 0.0, $
            overlap_fraction : 0.0, $
            observation_count : 0.0, $
            on_flag : 0}

   lut = replicate(table, attributes.nsfc)

   channels_used = {wvl : intarr(attributes.nchan_used)}