No abstract available

[en] It is shown that the maximum of the present 80-year sunspot period, as the period of the importance of sunspot groups, occurred in 11-year cycle No. 18 (1944 to 1953) according to the Zurich numbering. (author)

[en] Using the McMath solar telescope on a morning of average seeing it has been found possible, with the help of photoelectric speckle interferometry, to detect securely the existence of details in the quiet solar granulation up to a wavenumber of 240times10/sup -4/ km/sup -1/, i.e., a wavelength of one-third of an arc second

No abstract available

[en] Eighty one sunspots, which evidently went extinct on the visible disk between 1963 and 1970 and which had reached J type of the Zurich classification in their development, are studied. It was found that the intensity of their magnetic field several days prior to the extinction of the sunspot suddenly increases up to the secondary maximum of intensity and that it then goes extinct. Two characteristic shapes of the secondary maximum were observed. (author)

[en] Using sunspot positions of small sunspots observed at Debrecen and Locarno as well as positions of recurrent sunspots taken from the Greenwich Photoheliographic Results (1940-1976) the influence of the Wilson depression on the rotation velocities was investigated. It was found that the Wilson depression can be determined by minimizing errors of the rotation velocities or minimizing the differences of rotation velocities determined from disk passages and central meridian passages. The Wilson depressions found were between 765 km and 2500 km for the first sample while they were between 0 km and several 1000 km for the second sample. The averaged Wilson depression for the second sample is between 500 km and 965 km depending on the reduction method. A dependence of the Wilson depression on the age of the spots investigated seems not to exist. (orig.)

[en] Interplanetary magnetic field data compiled by King (1977, 1979) are used to obtain a list of high velocity solar wind streams for the period January 1975 through June 1978. The catalogue is a continuation of a previous list which covered 1964-75. The total number of high-speed solar wind streams listed in the catalogues is 455. (orig.)

No abstract available

[en] In this paper we review some of the changes that have taken place on the time scale of from two to ten decades in the frequency and latitude of occurence of the aurora in the region near and south of the present auroral oval. We relate these changes, qualitatively to solar wind parameters. The review is in two sections based on the primary data source used. (orig./WL)

[en] Some estimations for the vertical gradient of the sunspot magnetic field have been obtained under the similarity assumption. It is proved that the assumption is incompatible with large values of the vertical gradient. The greater the size of the sunspot is the smaller is its permissible value of dH/dz. (orig.)