ARCSDI-Corrects for arc line curvature

Description:

Program to allow correction of 2-d spectra for S-distortion using an arc - as a preliminary stage prior to wavelength calibration and scrunching. The lines are located by fitting gaussians to them. These positions are then used to fit a chebyshev polynomial to - one for each line. The intermediate positions are interpolated from these. Once this is done the data are shifted and interpolated in the x-section direction to align them all.

Parameters:

IMAGE

IMAGE = FILE (Read) Name of image for input This should be a file containing an arc spectrum.

ARC_OPTS

ARC_OPTS = CHARACTER (Read) Enter arc fit option NEW : set up a new wavelength calibration REPEAT : Itterate on previous calibration. CLONE : CLone a previous calibration. OLD : Correct using previous results

OUTPUT

OUTPUT = FILE (Write) Name of output file File to contain corrected data.

YSTART

YSTART = INTEGER (Read) analysis lower limit The data between the limits ystart and yend is extracted and the resultant spectrum is used to locate the lines.

YEND

YEND = INTEGER (Read) analysis upper limit The data between the limits ystart and yend is extracted and the resultant spectrum is used to locate the lines.

YBLOCK

YBLOCK = INTEGER (Read) Enter analysis x-sect width Each window is of this width (except perhaphs the final one).

ITERATION

ITERATION = INTEGER*2 (Read) New value of iteration

ORDER

ORDER = INTEGER (Read) order for polynomial fitting This is for the continuity correction of the data. Idealy the arc should have been pre-processed with ARCSDI, so a low order e.g. 2 should be used.

MAXLINES

MAXLINES = INTEGER (Read) Maximum number of lines to allow room for This must be greater than or equal to the number of lines fitted, so room should be allowed in case any more are to be added later.

CLFILE

CLFILE = FILE (Read) Name of image for cloning from This should be a file containing an arc spectrum.

TOLS

TOLS = CHARACTER (Read) For use in batch only

KEEP_ITT

KEEP_ITT = LOGICAL (Read) keep itteration files'

PRFITS

PRFITS = LOGICAL (Read) Print out details of fitting

PLOTCORR

PLOTCORR = LOGICAL (Read) Plot correction?

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