Next: 10.5 Extinction Correction Up: 10 MORE WAYS TO Previous: 10.3 Cross-Correlating Two Spectra

10.4 Coadding Spectra

IUE spectra can be combined to increase the signal to noise ratio. The procedure COADD will perform coaddition. The files used as input do not have to have identical wavelengths; COADD will resample any spectra that do not match the FIRST spectra entered.

COADD,SPEC,ELIM,WOPT,CNAME,/newsips

SPEC The number of spectra to be coadded or a string array of filenames. You may also enter an argument for FINDFILE (e.g., 'SWP*.SAV'). If SPEC=0, the user is prompted for input.
ELIM Possible values are:
$\epsilon$ Cutoff $\epsilon$ value for weighting. Only points >ELIM will be considered good data. IUESIPS only.
$\nu$ The specified bit setting(s) of ( $\nu$ ) will be considered bad. You may use the procedure NUFLAGS to generate a value for ELIM. NEWSIPS only.
0 The user is prompted for input.
>0 All points are included.
WOPT Exposure weighting option:
0 Prompt user for input.
1 Use SQRT(exposure time) for weighting.
2 Use exposure time for weighting.
3 Uniform weighting of spectra.
4 Prompt user for constant weight for each spectrum.
5 NEWSIPS only: use $\sigma$ values. Will not work if wavelengths are interpolated.
CNAME Name of output file (less than 8 characters). If CNAME=' ', the user is prompted for the name.
newsips If SPEC is a number, COADD will assume that input files are IUESIPS RDAF.SAV files unless this keyword is set.

Next: 10.5 Extinction Correction Up: 10 MORE WAYS TO Previous: 10.3 Cross-Correlating Two Spectra

2/9/1998

SPEC	The number of spectra to be coadded or a string array of filenames. You may also enter an argument for FINDFILE (e.g., 'SWP*.SAV'). If SPEC=0, the user is prompted for input.
ELIM	Possible values are: $\epsilon$ Cutoff $\epsilon$ value for weighting. Only points >ELIM will be considered good data. IUESIPS only. $\nu$ The specified bit setting(s) of ( $\nu$ ) will be considered bad. You may use the procedure NUFLAGS to generate a value for ELIM. NEWSIPS only. 0 The user is prompted for input. >0 All points are included.
WOPT	Exposure weighting option: 0 Prompt user for input. 1 Use SQRT(exposure time) for weighting. 2 Use exposure time for weighting. 3 Uniform weighting of spectra. 4 Prompt user for constant weight for each spectrum. 5 NEWSIPS only: use $\sigma$ values. Will not work if wavelengths are interpolated.
CNAME	Name of output file (less than 8 characters). If CNAME=' ', the user is prompted for the name.
newsips	If SPEC is a number, COADD will assume that input files are IUESIPS RDAF.SAV files unless this keyword is set.