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% @(#)flat_eche.hlq 19.1 (ESO-IPG) 02/25/03 14:18:34
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%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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%.COPYRIGHT (c) 1990 European Southern Observatory
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%.KEYWORDS MIDAS, help files, FLAT/ECHELLE
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%.PURPOSE On-line help file for the command: FLAT/ECHELLE
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%.VERSION 1.0 04-MAR-1991 : Creation, PB
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%----------------------------------------------------------------
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FLAT/ECHELLE 04-MAR-1991 PB
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FLAT/ECHELLE [flat] [correct] [blaze]
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subtract background from flat-field image and approximate blaze profile
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a) optionally subtract background from flat-field image
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If the descriptor BACKGROUND exists in flat-field image,
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the background step will be skipped.
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The corrected image, i.e. the flat-field corrected
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from its background, is stored as [correct]
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b) compute an approximation to the blaze profile for the
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flat-field. The order-by-order blaze profiles are stored
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The output images are used for flat-field correction.
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The background is approximated by spline polynomials
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fitted to points located in the interorder space.
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These points are defined by the command DEFINE/ECHELLE
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Parameters can be defaulted to the current session values,
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as displayed by SHOW/ECHELLE.
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FLAT/ECHELLE [flat] [correct] [blaze]
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flat = flat-field image
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correct = flat-field image with background subtracted
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blaze = profile of the blaze function
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Default values are read from echelle keywords in sections
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2. Background and 8. Flat-Field
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FLAT/ECHELLE ffima ffcor blaz