000001911 001__ 1911
000001911 005__ 20160701171655.0
000001911 037__ $$aASTROimport-68
000001911 100__ $$aVerschueren, W.
000001911 245__ $$aOrder extraction and background subtraction on CCD CASPEC echelle spectra
000001911 260__ $$c1990
000001911 520__ $$aThe standard MIDAS reduction package have been investigated for echelle spectra using CASPEC CCD data obtained in the blue wavelength region. A number of numerical limitations, present in some reduction steps, are found to reduce the final accuracy attainable with the instrument. In a first paper, a new algorithm for a more precise wavelength calibration was described. Here, three new algorithms are presented, operating within the MIDAS environment, for order detection, background subtraction and order extraction, and compared with the standard procedures. It is shown that the proposed algorithms eliminate the ripple induced by integration over inclined orders and allow a more accurate representation of the background light distribution over the frame. The basic ideas behind the improvements are generally applicable to the reduction of other echelle data. 
000001911 700__ $$a Hensberge, H.
000001911 773__ $$c216-222$$pAstronomy and Astrophysics$$v240$$y1990
000001911 85642 $$ahttp://esoads.eso.org/abs/1990A%26A...240..216V
000001911 905__ $$apublished in
000001911 980__ $$aREFERD