Astron. Astrophys. Suppl. Ser. 135, 227-229

Solar diameter observations at Observatório Nacional in 1997-1998

E.G. Jilinski¹² - S. Puliaev¹² - J.L. Penna¹ - A.H. Andrei¹ - F. Laclare³

Send offprint request: E.G. Jilinski, Observatório Nacional/CNPq, R. Gal. José Cristino 77, CEP20921-400, Rio de Janeiro, Brasil. E-mail: jilinski@on.br

1 - Observatório Nacional/CNPq, Brasil
2 - Pulkovo Observatory, Russia
3 - CERGA/Observatoire de la Côte d'Azur, France

Received July 24; accepted October 2, 1998

Abstract:

In January 1997, at the Observatório Nacional (ON), Rio de Janeiro, Brazil, CCD observations of the solar diameter with a Danjon astrolabe equipped with a variable angle reflecting prism began. This prism is operated manually and enables to observe the Sun many times per day and all year round on the Southern latitude $\varphi = -22^\circ 54'$.

Thanks to this and owing to a large number of sunny days at Rio de Janeiro, a high density of observations was achieved - 2900 East and 1730 West observations during the first 18 months.

Results of the observations are available in electronic form in the SIMBAD database and at the World Wide Web page of the Observatório Nacional, Solar Radius Data: http://obsn.on.br/radius/.

Key words: Sun: general; fundamental parameter