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Data on compact magnetic features and hydrogen Hα filaments during solar activity cycles 20 and 21 are used to study variations in the solar differential rotation. The difference in the differential rotation rates of the compact magnetic features and hydrogen Hα filaments is greatest between the 20-30° and 30-40° latitude zones in both solar hemispheres. The rotation rates of the compact magnetic featuresat all latitudes are higher than those of the hydrogen Hα filaments and the difference between them increases with latitude. [ABSTRACT FROM AUTHOR]

The rotation of the solar coronal holes was studied. Data from the Kitt Peak Observatory in the line 10830 Å He I for 2003-2012 was used for this purpose. The rotation of 434 coronal holes in the latitude interval ±40° was studied. The maximum angular velocity is observed at latitudes ±15°. Coronal holes have a lower angular velocity (13.39 deg/day) and rotate less differentially than the solar photosphere. [ABSTRACT FROM AUTHOR]

Variations in the solar differential rotation have been studied at the moment of the polarity reversal of the sun's general magnetic field in solar activity cycles 20 and 21. Data on Hα filaments obtained at the Abastumani Astrophysical Observatory and on compact magnetic features from an atlas of synoptic charts were used. Before and after a single polarity reversal of the solar magnetic field (cycle 21), a higher rotation rate was observed for compact magnetic features with the polarity of the circumpolar magnetic field than for the oppositely polarized features. In the case of a triple polarity reversal of the solar magnetic field (cycle 20), this pattern was disturbed. The variations in the rotation rate of compact magnetic features with both negative and positive polarities differ from the rotation rates of hydrogen filaments at times when the solar general magnetic field undergoes a polarity reversal. [ABSTRACT FROM AUTHOR]

The time variation and latitude dependence of the solar rotation are found using observational data on Hα filaments and compact magnetic features with different polarities during solar activity cycles 20 and 21 (1966-1985). Statistical analysis of the observational data shows that there is a north-south asymmetry in the rotation, both for the Hα filaments and for compact magnetic features (structures) with negative and positive polarities. The N-S asymmetry in the differential rotation of the Hα filaments and the compact magnetic features with both polarities shows up quite distinctly in solar activity cycles 20 and 21, but the asymmetry for the compact magnetic features with positive polarity is comparatively lower in cycle 21. The confidence level is lower the compact magnetic features with positive polarity than for the compact magnetic features with negative polarity. [ABSTRACT FROM AUTHOR]