NAME

vigcompute -- Compute the GHRS vignetting function.

USAGE

vigcompute input wave table output

DESCRIPTION

This routine computes the GHRS vignetting function (i.e., low frequency variations in photocathode response and light loss from baffles). The vignetting function is computed as the ratio of the GHRS flux (reduced with all standard reduction steps in calhrs except the vignetting correction) and the standard star flux of the observed object interpolated (linear interpolation) to the same wavelength scale.

PARAMETERS

input [file name]

Name of the reduced GHRS observation flux image.

wave [file name]

Name of the file containing the wavelengths for the input flux image.

table [file name]

Name of the table containing the true flux values for the observed object. It must have columns of WAVELENGTH and FLUX.

output [file name]

Name of the output image to contain the unsmoothed vignetting values. It has the same length as input.

EXAMPLES

1. Compute the vignetting function for input observations, flux and wave, using the associated standard star table, startab. Results are written to the output image, vig.

  hr> vigcompute flux wave startab vig

BUGS

REFERENCES

HELP

For assistance using this or any other tasks, please contact help@stsci.edu or call the help desk at 410-338-1082.

SEE ALSO

vigfit