Calibration and Data Reduction

1
Calibration and Data Reduction
2
Issues The Usual

• Darks (treated in the usual manner)
• Cosmic rays (treated in the usual manner)
• Bad Pixels (treated in the usual manner)
• Distortion (Goes away in the conversion from
  focal plane to data cube)
• Plus we seem to have very little

3
Issues The UnusualFlat Fielding and Calibration

• Both are made difficult by the nature of the
  device a low resolution spectrometer and the
  fact that the QE is function of wavelength.
• In fact varies by 20 between 1 and 1.8 microns.

4
How Hungry Are You and When do Want to Eat?

• Deduced spectra are most accurate when the
  spectrum of a observed object is the same as the
  one used for flat fielding.
• That not being the case, the quality of the
  detected spectra may depend on how much time
  youre willing to spend in the kitchen and to
  what end.

5
Whats on the Menu

• Assume that the QE is flat Flat field with a
  G-star
• Assume the QE of each pixel is equal to the
  average of it and a joining pixels Flat Field
  with a G star
• Assume nothing Calibrate with a monochromator
  Develop algorithms for deconvoluting the data.

6
What the Cook Suggests

• Method two.
• Plus the no extra salt option.
• Use only two rows in each spectrum the third and
  four contain low S/N data and increased
  contamination from adjacent spectra.

7
Will it be satisfying?

• Certainly as a snack and possibly quite filling.
• Remember, the primary purpose of a CIFU is to aid
  in detection, not necessarily to be a full course
  meal.
• Photometrics for astrometry are still possible on
  collapsed images which can and will be flat
  fielded separately.