The MG II H and K lines. I - Absolute center and limb measurements of the solar profiles

We report new measurements of the solar Mg II h and k lines with uncertainties in the absolute intensities at k1 and h1 of - 20 to + 12 percent with smaller uncertainties for higher intensities. The spectral resolution, defined by the full width at half-maximum of the instrumental profile, was 0.028 A, and the angular resolution element was 184" by 1,5. Measurements were made for a quiet region near the disk center and for a quiet region at cos 0 = 0.23. The measured profiles are suitable for detailed comparisons with theoretical solar and stellar profiles, as will be discussed in the paper by Ayres and Linsky (Paper II) that will follow in a later issue. Our measured minimum intensities (k1 and h1) relative to the core intensities (k3 and h3) and to the average peak intensities (k2 and h2) are fainter than the corresponding intensities that were reported by Lemaire and Skumanich. Subject headings: line profiles - Sun: spectra - ultraviolet: spectra