Volume 375, Number 2, August IV 2001
|Page(s)||614 - 616|
|Section||Planets and planetary systems|
|Published online||15 August 2001|
Astrometric observations of the Sun at Santiago: 1998-2000*
Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
Accepted: 23 April 2001
A program of solar astrometry with a modified Danjon astrolabe has been in progress since 1990 at the National Astronomical Observatory at Cerro Calán, Santiago, Chile. More than 3200 homogeneous observations have been made visually by a single observer at and zenith distances. Here we present and discuss the results in right ascension, parameter Y and apparent solar radius obtained during the period 1998-2000. These results and those obtained in former years are available in electronic form. After almost 11 years of continuous observations, the most interesting aspect of the solar results of the Santiago astrolabe is a significant and positive correlation between variations in time of the apparent semidiameter of the Sun and solar activity.
Key words: astrometry / Sun: activity / Sun: fundamental parameters
© ESO, 2001
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