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map-spectra

map-spectra calculates the mapping between science plane (wavelength and slit coordinate) and CCD focal plane for a given observation set.

 

USAGE	map-spectra observset
INPUT	observset.obsdef name of an existing observation definition file
OUTPUT	observset.map is a file with the mapping information
PARAMETERS	minlambda minimum wavelength maxlambda maximum wavelength minpixl minimum number of pixels of spectrum on a chip use_partial map partial slits use_holes map alignment holes as well as slits

 

Details:

map-spectra first finds, for each slit, spectrum segments- ranges of wavelength- that fall on each chip. Wavelengths at which the object position along the slit is too close (a few pixels) to the chip edge are not included. If minpixl is set to a non-zero number, shorter segments are discarded. map-spectra does not map partial slits, those with an end which falls off the edge of the CCD at any wavelength, unless use_partials is set to “y”. If partial slits are mapped, map-spectra finds the wavelength at which the smallest fraction of the slit is on a ccd, and uses this length for the entire spectrum. Slits that are not mapped, and partial slits that are mapped, are reported when the program exits. You must set use_holes to "y" if you intend to use the alignment stars during the extraction in extract-2dspec.

·      partial slits may require special handling in later steps of the reduction. See the documentation of adjust-map and the COSMOS Cookbook for details.

·      map-spectra may not handle slits that are longer than the width of a ccd chip.

 

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