Astrometric observations of the Sun at Santiago: 1998-2000*
Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago, Chile
Received:
20
February
2001
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