NAME

fitring -- compute the dispersion solution using the ring parameters

USAGE

fitring ringfile output

PARAMETERS

ringfile

the text file containing the ring parameters, most likely the output file from RINGPARS.

output

text file name for the output summary.

insdel = ""

control parameter for user input to the fit. May be either "d" to delete an entry from the fit, "i" to insert a previously deleted entry, or "q" to qut and accept the current fit.

del_line =

the line number to be deleted if "insdel" was set to "d" during the fitting.

ins_line =

the line number to be re-inserted if "insdel" was set to "i" during the fitting.

DESCRIPTION

The ring parameters, radius, wavelength, and etalon gap are fit to an equation of the form:

Lambda = (A + B*z) * Cos (Atan (R/C))

to determine the constants A, B, and C. The results of the fit are presented in tabular form, and the user may delete ("d") an outlying entry. Once deleted, an entry can be reinstated ("i"). To accept the presented solution, a "q" will exit the query loop, and write the solution to the "output" file.

The constants A, B, and C are later used by the task VELOCITY to determine the wavelengths of each pixel in the image cube.

EXAMPLES

For a ringfile named "rings", compute the constants A, B, and C. The solution is written to the file "constants".

cl> fitring rings constants

TIME REQUIREMENTS

Doesn't do much, but does it very fast.

BUGS

Probably doesn;t work if there are only 3 entries in the ring parameter file, even though a solution is possible.

SEE ALSO

RINGPARS, VELOCITY