ARC2D-Calibrates distortions in 2D arc line data.

Description:

This program controls both 1D and 2D wavlength calibration and can operate either in BATCH or INTERACTIVE modes. The philosophy behind it is somewhat different to those presented in the existing SPICA/SDRSYS and FIGARO software in many respects. In particular its exclusive use of gausian fitting of arclines, its demand for "intellegent" users, who can decide which lines they want to use initially and then allow them to make objective assesments of which,if any are erroneous. Typical diagnostic information given are plots of residuals from the fit versus line width,flux and position. This is all made possible by the use of the Gaussian fitting. The least squares polynomial fitting allows weights to be included for each line(again derived from the formal Gaussian fits).Thus it is possible to constrain the polynomial in difficult regions eg "the 5100 gap" without distorting the global fit.

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

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

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