seeking help regarding single-exposure of DESI

Question

Hi,

Does the DESI data include single-exposure spectral data, and if so, what is its typical signal-to-noise ratio, and does the subsequent DESI data still contain single-exposure spectra? Thanks!

Answer 1

Yes, single exposure spectra are provided in spectra files that accompany each coadd file. For example, for the coadded spectra in coadd-main-dark-18939.fits, there is a spectra-main-dark-18939.fits.gz that contains the individual exposures.

For details on these file types, see coadd-SURVEY-PROGRAM-PIXNUM.fits and spectra-SURVEY-PROGRAM-PIXNUM.fits.

Comments

Further details: in those coadd and spectra files, the SCORES table has MEDIAN_CALIB_SNR_B/R/Z which gives the median signal-to-noise ration per sqrt(Angstrom) for the flux calibrated spectra for each of the 3 cameras B, R, and Z.  Typical values are O(1).