Summary of Dark level, Readout-noise and 
their time-variations of both camera 



* Dark frames of GE1650 were measured by H.Watanabe on 13th Mar. 2007.
* Dark frames of ORCA-AG were measured by T.Matsumoto on 21th Mar. 2007.
* A/D: 12 bit, BIN: 2x2, Exposure time: 80 ms, Frame Rate: 12 Hz, Gain: 0
* Continuous 16 frames were grabbed in 13 times at every 10 min.
* Total duration is 120 min.
* So, the number of all frames is 16x13 = 208 frames.
* We consider the RMS of all pixels of eash CCD-chip 
  as the typical level of the readout-noise.





[GE1650 results]
 * After about 40 min, dark-level becomes stable
   whose value is 26.6 DN (= 0.65 % of 12 bit FullWell).
 * The size of typical readout-noise is about 8.1 DN (= 0.20 % of 12 bit FullWell).
   (FullWell = 20,000 e-)

[ORCA-AG results]
 * After about 10 min, dark-level becomes stable
   whose value is 192.4 DN (= 4.7 % of 12 bit FullWell).
 * The size of typical readout-noise is about 1.6 DN (= 0.04 % of 12 bit FullWell).
   ( FullWell = 18,000 e- )







[Comparison between GE1650 and ORCA-AG]

Estimated sizes of noises of both cameras 
that are calculated from actually measured readout noises and dark levels.








Actual Ca K Line Profile obtained with GE1650 and ORCA-AG,
on the only one line of the each CCD-chip.

 1) On the solar disk (GE1650: 2007/03/09, ORCA-AG: 2007/03/26)
  

 2) Dark prominence (GE1650: 2007/03/16, ORCA-AG: 2007/03/21)