* Astronomy

Members Login
Post Info TOPIC: Solar astrometry


L

Posts: 131433
Date:
RE: Solar astrometry
Permalink  
 


Title: 42 Years of Continuous Observations of the Solar Diameter from 1974 to 2015
Author: Alexandre H. Andrei, Sergio C. Boscardin, Jucira L. Penna, Nelson V. Leister, Costantino Sigismondi

Several group in the World followed the solar diameter with dedicated instruments, namely solar astrolabes, since 1974. Their data have been gathered in several observing stations connected in the R2S3 (Reseau de Suivi au Sol du Rayon Solaire) network and through reciprocal visits and exchanges: Nice/Calern Observatory, Rio de Janeiro Observatorio Nacional/Brazil, IAG/Universidade de Sao Paulo/Brazil, Antalya Observatory/Turkey, San Fernando/Spain. The tradition of these observational efforts is here briefly sketched with the aim to evidence the possibility to analyse against the solar activity all these 42 years data at once by overcoming the problem of the shift between the different series. Each instrument has its own density filter with a prismatic effect responsible of that shift. The overall change of the solar radius during the last century is evident by comparing the Auwers' radius of 959.63" (1891, present IAU standard) with 959.94" (2015, from eclipses and Venus transit data, the latter either observed from space) and the role of ground-based daily measurements has been and it is crucial nowadays with Picard-sol and the Reflecting Heliometer of Rio de Janeiro, to ensure an homogeneus and continuous monitor of the solar diameter without the lifetime limitation of the satellites.

Read more (712kb, PDF)



__________________


L

Posts: 131433
Date:
Permalink  
 

Title: Solar astrometry: the status of art in 2011
Authors: Costantino Sigismondi

Solar astrometry deals with the accurate measurement of the solar diameter, and in general with the measurement of the shape of the Sun. During the last decades several techniques have been developed to monitor the radius and the irradiance of the Sun: meridian transits, telescopes in drift-scan mode, solar astrolabes, balloons, and satellites dedicated to the measurements of the solar diameter, and space measurements of the total solar irradiance are now performed to know the relationship radius-luminosity for the Sun in this evolutionary stage of its life. The feedback of solar astrometry in climate studies is of paramount importance. The status of art in the various fields of research addressed here is outlined.

Read more (17kb, PDF)



__________________
Page 1 of 1  sorted by
 
Quick Reply

Please log in to post quick replies.



Create your own FREE Forum
Report Abuse
Powered by ActiveBoard