;$Id:$
   ;-------------------------------------------------
   ; make a structure to hold data and attributes
   ;-------------------------------------------------
   table = {clear : fltarr(attributes.nbins_x), $
           ice : fltarr(attributes.nbins_x), $
           water : fltarr(attributes.nbins_x), $
           obs : fltarr(attributes.nbins_x), $
           cloud_fraction : 0.0, $
           ice_fraction : 0.0, $
           water_fraction : 0.0, $
           observation_count : 0.0, $
           on_flag : 0}

   lut = replicate(table, attributes.nsfc)

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