Test of Making Flat



(1) An original spectrum image
    We can see fringe patterns and some dusts.



(2) Summed spectrum image during discontinuous 50 sec (discontinuous 604 frames)
    with scanning on the Quiet Region



(3) Averaged image of (2) along wavelength-direction and spatial-direction, respectively 



(4) Artificial Flat-frame made from (2)/(3)
    Though some patterns of absorption lines are still included,
    we can clearly detect fringe and dust patterns.



(5) Spectrum image divided by the Flat-frame: (1)/(4).
    Almost fringe and dust patterns are reduced.