SMARTS 1.5m reduced spectral format The reduced data are saved in a FITS file. The data are saved in an N x M vector. N is the number of points along the spectrum. M is 6 if background is subtracted, and 4 otherwise. If the data are flux calibrated, then M=8 or 6. If background has been subtracted, the individual vectors are: M=0: background-subtracted spectrum extracted using boxcar extraction M=1: background vector extracted using boxcar extraction M=2: error on the spectrum M=3: error on the background M=4: spectrum extracted using a Gaussian extraction M=5: background vector extracted using Gaussian extraction M=6: flux/count. Multiply data(*,0) x data(*,6) for the flux. M=7: flux/count. Multiply data(*,1) x data(*,7) for the flux. If no background has been subtracted, the individual vectors are: M=0: spectrum extracted using boxcar extraction M=1: error on the spectrum M=2: spectrum extracted using a Gaussian extraction M=3: background vector extracted using Gaussian extraction M=4: flux/count. Multiply data(*,0) x data(*,4) for the flux. M=5: flux/count. Multiply data(*,1) x data(*,5) for the flux. The wavelength vector is linear, with the wavelength of the first point and the reciprocal dispersion (A/bin) given in the header keywords WAVE_0 and DELTA_W, respectively Extraction methods: Boxcar extraction: Extract counts within +/- X pixels of the peak. Extract background in regions to either side of peak. Subtract median background level. The default width is determined by fitting a Gaussian to the spatial cut. This method can give more accurate absolute fluxes, because the extraction region widths can be set by hand. Gaussian extraction: Fit the spectrum in the cross-dispersion direction with a Gaussian. The extracted flux is the integral of the fitted Gaussian, so it is less susceptible to cosmic rays in the spectrum. A gaussian often fits the wings poorly when the seeing is poor (or even average), and so generally gets fewer counts than the boxcar extraction. The Gaussian extraction does not do a good job if there is another bright source nearby.