code: def getReadNoiseImage(self, chip):
          
          sci_chip = self._image[self.scienceExt,chip]
          return np.ones(sci_chip.image_shape,dtype=sci_chip.image_dtype) * sci_chip._rdnoise
docs: Notes
          =====
          Method for returning the readnoise image of a detector
          (in electrons).
  
          The method will return an array of the same shape as the image.
  
          :units: electrons