NAME

mergecar -- Merge GHRS spectra for absolute sensitivity calibration.

USAGE

mergecar input wave mask table delw

DESCRIPTION

Merge observations from multiple carrousel positions into a single spectrum of equally spaced wavelength bins. When spectra overlap or multiple points fall within a single bin, an average is taken. All spectra must be for the same grating mode.

The input spectra should be in corrected count rates with all standard reduction steps completed---except for correcting absolute sensitivity.

The output of this routine is used by the abssenz task to compute the unsmoothed sensitivity curve.

PARAMETERS

input [file name template]

Files containing the input spectra; these spectra must be for the same grating mode and should be in count rates.

wave [file name template]

Wavelength images corresponding to the spectra images specified by input. There must be one wave image for each input image.

mask = " " [file name template]

Optional mask images for each input image. Masks can be used to delete spectral lines, bad data points, or telemetry dropouts. If mask is set to " " then all data is assumed good. If a file name is supplied for mask, then every file indicated by input must have a corresponding mask file.

table = "mergecar" [file name]

Output flux table. This is the table used by the abssenz task; it contains the following columns:

     'WLOW'    - Lowest wavelength in the range (double).
     'WHIGH'   - Highest wavelength in the range (double).
     'FLUX'    - Average flux (double).
     'NPOINTS' - Number of data points averaged for the bin (integer).

delw = 1.[real, min=0.1, max=100.0]

Floating point number giving the output wavelength bin size.

EXAMPLES

1. Merge data in the spectra images flux1, flux2, and flux3 with wavelength images, wave1, wave2, and wave3; put the results in the output table fluxmerge.tab. Use a wavelength bin size of 5.0 Angstroms.

hr> mergecar flux1,flux2,flux3 wave1,wave2,wave3 fluxmerge 5.0

BUGS

REFERENCES

The document describing the GHRS is "SI Systems Description and User's Handbook for the High Resolution Spectrograph (HRS) for the Hubble Space Telescope (HST)", Ball Aerospace, SE-01.

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

abssenz, absfitz