Résultats de recherche pour « Taches solaires »

Introduction . Ten years have passed since the last Congress and so much has been published since then in the field of photospheric and allied phenomena that this can only be a summary and not an exhaustive report. Periodicity of Sunspot Activity . The long period already established by R. Wolf in 1862, has again been investigated by W. Gleissberg ( Publ. Istanbul Obs. No. 14, 1941; No. 15, 1941; Z. Ap. 21, 347, 1942; Ap. J. 96, 234, 1942), with the result that the period amounts to approximately 70 years.

Mr Royds writes: “The original scheme for daily character figures called for integers ranging from 0—5 to characterise the solar activity for bright and dark flocculi. Since then it has appeared to some observatories to be desirable, particularly as the spot cycle has approached its minimum, to quote character figures intermediate between whole integers. Many observatories have introduced 0.5, 1.5, 2.5, etc., in addition to whole integers, whilst others have also used 0.2, 0.7, 1.2, etc. It seems to me that sufficient experience has now been gained to decide how far this subdivision between whole integers is to be carried. Kodaikanal would be willing to revert to the original proposal of whole integers on the scale 0.5. If it is considered desirable to interpolate half integers, I suggest that whole integers on the scale 0-10 would be easier to print and to read.”

Periodicity and new properties of the frequency curve . Bruno Hanisch uses the method of autocorrelation introduced by W. Pollack in geophysics for the discovery of periods in the frequency series of sunspots from 1794 to 1925. Dividing the whole interval into three sections he finds an eleven- and an eight-year period common to the three sections, whereas other periods found in the three sections differ widely from each other. The new method gives for the length of the main period II-8 years for the interval 1880 to 1925. This result agrees strikingly with the revolution period of Jupiter (Gerlands Beiträge zur Geophysik , 46, 1935).