VARIATIONS OF THE APPARENT SOLAR SEMIDIAMETER OBSERVED WITH THE ASTROLABE OF SANTIAGO

Measurements of the Sun semidiameter made with the Danjon astrolabe at Santiago, Chile, and with the magnetograph of the solar telescope of Mount Wilson Observatory during the period 1990-1995, show similar var iations in time and with a similar trend as the variation of sunspot n umber. The consistency of these results obtained at different sites an d with rather different observing techniques could be considered as an empirical evidency that a causal connection may exist between the sol ar activity and the variations of the apparent solar radius as observe d at Santiago and Mount Wilson.