Issue |
Astron. Astrophys. Suppl. Ser.
Volume 123, Number 2, June I 1997
|
|
---|---|---|
Page(s) | 403 - 410 | |
DOI | https://doi.org/10.1051/aas:1997164 | |
Published online | 15 June 1997 |
Discussion of the results from solar astrolabes
1
Observatorio Nacional/CNPq, Brasil
2
Instituto Astronômico e Geofísico/USP, Brasil
3
Observatoire de Calern/OCA, France
Corresponding author: Send offprint request to: J.L. Penna, Observatorio Nacional/CNPq, R. Gal. José Cristino 77, CEP 20921-400, Rio de Janeiro, e-mail: jucira@on.br
Received:
12
June
1996
Accepted:
25
September
1996
In this work we investigate
on the stability of the results from solar observations obtained
with the modified astrolabes of the Observatoire de la Côte
d'Azur/France, of the Observatório Abrahão de
Moraes/IAG/USP-Brazil and of the Observatório
Nacional/Brazil. The mass of data is comprised of 6273
observations of both solar limbs, from 1974 to 1992, and is
analyzed to determine the origin of the fundamental reference
system and the Earth's orbital parameters.
The solution stability was verified by checking against any large variation
upon the individual weights, as well as for different sub samples
of the whole set of observations. The results were also shown
invariant to changes in the adopted model, such as adding unknowns
to the refraction algorithm, to the time variation of the obliquity
(including the nutation constant) and to the azimuthal anomalies of
the refraction.
In our analysis we obtain a standard deviation of for the
combination of the observations with no bias on its distribution. It is
also indicated that the Sun observations at astrolabes do not require any
further atmosphere modelling complexity.
Key words: astrometry / reference system / Sun: general / methods: data analysis
© European Southern Observatory (ESO), 1997