A Fourier analysis of sunspot activity during the 1933-1954 period using data entending over the first 10 degrees and all azimuthal orders of the spherical harmonics is presented, and results suggest that the sunspot ...

Measurements are presented, made on March 24, 1991 over the Kodaikanal, showing that, around sunset, the Doppler velocity of F-region reflections at vertical incidence is influenced by MHD waves, the magnetic effects of ...

Spectrophotometric observations of the hot Si star HD 34452 = HR 1732 obtained over a duration of four years, from 1979 to 1983, are presented. The period of variation in the broad-band feature centred around λ5200 is found ...