next previous
Up: A catalogue of accurate Sun


2 The source atlases

Among other solar flux FTS atlases, the Solar Flux Atlas from 296 to 1300 nm (Kurucz et al. 1984), which is available from the NOAO[*] ftp site, provided us with a high-quality spectrum of the Sun seen as a star. It was obtained at the McMath[*] telescope at Kitt Peak.

The FTS disc-centre spectrum included in the newer Spectral Atlas of Solar Absolute Disk-Averaged and Disk-Center Intensity from 3290 to 12510 Å (Brault & Neckel 1987; for details see Neckel 1994) was also obtained at the McMath telescope. The wavelengths of selected lines from the table of Pierce & Breckinridge (1973), which was produced from observations with a grating spectrometer and a photographic detector at the same telescope, have been the base for placing its wavelength calibration on an absolute scale. We have measured line central wavelengths in this atlas, available to us as part of the IDL KIS[*] library. A flux spectrum is also contained in this FTS atlas, which shares the source data obtained by J. Brault and collaborators with the atlas prepared by Kurucz et al. (1984).

The atlases cited achieve signal-to-noise ratios of about 2500 and a resolving power $\lambda /\Delta\lambda \sim$ 400000. A quantitative basis for confidence in these atlases has been established by comparison between central wavelengths of 1446 FeI lines in the solar spectrum and at rest, performed by Allende Prieto & García López (1998). Briefly, they found:


next previous
Up: A catalogue of accurate Sun

Copyright The European Southern Observatory (ESO)