KOOLS: Kyoto Okayama Optical Low-dispersion Spectrograph

Information on Data Reduction

Under Construction

Data Reduction

No special data reduction software is planned. Please use your favorite software, like IRAF long slit reduction packages (noao.twodspec, noao.onedspec).

Important note: KOOLS raw data have BITPIX=16 (SHORT_IMG, signed integers). In order to properly treat them with the ossub program below and NOAO/IRAF spectroscpic data packges, you need to convert data type to BIPIX=-32 (FLOAT_IMG, 32-bit floating point). Under IRAF this can be done with the following command:

chpixtype @listin @listout real

Overscan Subtraction

  • ossub: a simple program for bias subtraction using median of an overscan region in each line. This requires CFITSIO. For geometry of overscan regions for different read-out modes, refer KOOLS operationsection.
  • NOTE: CCD受光面に光が入っている場合, overscan領域のカウントが高くなる現象が見られています. このため, 特に明るいobjectの場合, ossubで行っているように, 各lineでoverscan領域からbias値を求めると引き過ぎになると考えられますのでご注意ください.

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