Sunspot Catalogue of the Observatory of the University of Coimbra (1929 – 1941)
A sunspot catalogue was published by the Coimbra Astronomical Observatory (Portugal), which is now called the Geophysical and Astronomical Observatory of the University of Coimbra, for the period 1929 – 1941. We digitalised data included in that catalogue and provide a machine-readable version. We show the reconstructions for the (total and hemispheric) sunspot number index and sunspot area according to this catalogue and compare it with the sunspot number index (version 2) and the Balmaceda sunspot area series (Balmaceda et al. in J. Geophys. Res.114, A07104, 2009). Moreover, we also compared the Coimbra catalogue with records made at the Royal Greenwich Observatory. The results demonstrate that the historical catalogue compiled by the Coimbra Astronomical Observatory contains reliable sunspot data and can therefore be considered for studies about solar activity.
KeywordsSolar cycle, observations Sunspots, statistics
This work was partly funded by FEDER-Junta de Extremadura (Research Group Grant GR15137 and project IB16127) and from the Ministerio de Economía y Competitividad of the Spanish Government (AYA2014-57556-P and CGL2017-87917-P). JF, TB, and AL acknowledge support from the Fundação para a Ciência e a Tecnologia and Centro de investigação da Terra e do Espaço da Universidade de Coimbra Funds (UID/Multi/00611/2013) and ReNATURE (CENTRO-01-0145-FEDER-000007). Authors have benefited from the participation in workshops at the International Space Science Institute.
Disclosure of Potential Conflicts of Interest
The authors declare that they have no conflicts of interest.
- Bonifácio, V.: 2017, Costa Lobo (1864 – 1945), the Coimbra spectroheliograph and the internationalisation of Portuguese astronomy. In: History of Astronomy in Portugal, Imprimerie Centrale de l’Université de Nantes, Nantes, 113. Google Scholar
- da Costa Lobo, F.M.: 1929, Introdução, Anais do Observatório Astronómico da Universidade de Coimbra, Universidade de Coimbra, Coimbra. Google Scholar
- Hoyt, D.V., Eddy, J.A.: 1982, An atlas of variations in the solar constant caused by sunspot blocking and facular emissions from 1874 to 1981, National Center for Atmospheric Research, NCAR Technical Note TN-194+STR, Boulder, Colorado. Google Scholar
- Mouradian, Z., Garcia, A.: 2007, Eightieth Anniversary of Solar Physics at Coimbra, The Physics of Chromospheric Plasmas ASP Conference Series 368, Astronomical Society of the Pacific, San Francisco. Google Scholar