Magnetic Field of the Sun as a Star: The Mount Wilson Observatory Catalog 1970–1982

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Abstract
Measurements of the mean magnetic field of the Sun (MMFS) seen as a star were regularly conducted at the Mount Wilson Observatory from 1970 October through 1982 December. A listing is presented of all these data (2457 daily values) suitable for comparison with similar data of other observatories and for studies of magnetic variability and rotation of the Sun. The scatter-plot diagrams and power spectra of the Mount Wilson data and also of the total data 1968-1991 (collected from three observatories: Crimean Astrophysical Observatory, Mount Wilson Observatory, and Wilcox Solar Observatory) are also presented. Time variations of the MMFS connected with solar rotation at periods ≈ 27-28 days and also an enigmatic 1 yr variation are briefly discussed. The power spectrum of the 24 yr data set shows that the most significant and phase-coherent synodic periods of the MMFS variations are 26.92 ± 0.02 and 27.13 ± 0.02 days (both are thought to be associated with rotation of the large-scale surface magnetic field near equator of the Sun) and 28.13 ± 0.02 days. It is suggested that the latter period reflects "rigid" rotation of the global magnetic field concentrated under the bottom of the solar convection zone. The arguments are given in favor of reality and high confidence level of major periodicities exhibited by MMFS variations.