     @wfits = new astro.WebFITS(@el, @dimension)
     unless @wfits.ctx?
       alert 'Something went wrong initializing the context'
+      return
     
     # Load offsets if they exists
     @wfits.xOffset = @opts.xOffset or @wfits.xOffset

        })
    })
    
    band = @opts.band
    if band?
      if band is 'gri'
        @wfits.drawColor('i', 'r', 'g')
      else
        @wfits.setImage(band)
        @wfits.setStretch(@opts.stretch or 'linear')
    else
      # Default to color composite
      @wfits.drawColor('i', 'r', 'g')
    
    @trigger 'swviewer:loaded'
  
  updateBand: =>
    band = @opts.band
    
    if @wfits?
      if band is 'gri'
        @wfits.drawColor('i', 'r', 'g')
      else
        @wfits.setImage(band)
        @wfits.setStretch(@opts.stretch)
  
  updateAlpha: =>
    @wfits?.setAlpha(@opts.alpha) if @ready

    _.extend @, Ubret.Sequential
    
    super selector
    @collection = new Layers()
    @ready = false
    
