Solar Physics

, Volume 219, Issue 2, pp 379–384 | Cite as

On the solar activity during the year 1784

  • J.M. Vaquero


The solar observations performed by the Mexican astronomer J. A. Alzate during the year 1784 are analysed in this work. These observations are very valuable for the reconstruction of solar activity because Hoyt and Schatten (1998), who defined the Group Sunspot Number (RG), only found five observations during this year — all performed by J. C. Staudacher. Using conjointly the data provided by Alzate and Staudacher for 1784, one can determine a value of RG equal to 0.3±0.1 with eighty records for that year.


Solar Activity Sunspot Number Group Sunspot Solar Observation Group Sunspot Number 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Kluwer Academic Publishers 2004

Authors and Affiliations

  • J.M. Vaquero
    • 1
  1. 1.Departamento de Física, Escuela PolitécnicaUniversidad de ExtremaduraCáceresSpain

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