           width = cache[band].width
           height = cache[band].height
           @calibrations[band] = cache[band].calibration
+          @provenances[band] = cache[band].provenance
           
           @wfits.loadImage(band, arr, width, height)
           @dfs[band].resolve()

            @cache['prefix'][band].width = width
            @cache['prefix'][band].height = height
            @cache['prefix'][band].calibration = calibration
            
            @dfs[band].resolve()
          )
  

  getCalibration: (header) ->
    zeroPoint = header.get('MZP_AB')
    return Math.pow(10, 0.4*(30.0 - zeroPoint))
  
  getProvenance: (header) ->
    return header.get('PROV')
  
  # Call when all channels are received (i.e. each deferred is resolved)
  allChannelsReceived: =>
