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Sunspot Observations and Counting at Specola Solare Ticinese in Locarno Since 1957

  • Sunspot Number Recalibration
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Abstract

Specola Solare Ticinese is an observatory dedicated to sunspot number counting. It was constructed in 1957 in Locarno, Southern Switzerland, as an external observing station of the Zurich Federal Observatory. When the responsibility of the determination of the International Sunspot Number was assumed by the Royal Observatory of Belgium in 1981, Specola Solare Ticinese was given the role of pilot station, with the aim of preserving the continuity in the counting method. We report the observing procedure and counting rules applied in Locarno.

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Acknowledgements

The association ASST organizes the financing of Specola Solare Ticinese and was established by Alessandro Rima (who directed it from 1980 until 1991) and Paul Utermohlen. Jan Olof Stenflo at ETHZ recommended using Specola Solare Ticinese as the pilot station for SIDC in Brussels. Since 1992, ASST has been directed by Philippe Jetzer. Specola Solare Ticinese is mainly financed by the Ticino Canton through the Swisslos found. We thank Mario Gatti for helpful discussions.

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Authors and Affiliations

  1. Specola Solare Ticinese, Via ai Monti 146, 6605, Locarno, Switzerland

    Sergio Cortesi, Marco Cagnotti & Andrea Manna

  2. Istituto Ricerche Solari Locarno, Via Patocchi, 6605, Locarno-Monti, Switzerland

    Michele Bianda & Renzo Ramelli

Authors
  1. Sergio Cortesi
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  2. Marco Cagnotti
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  3. Michele Bianda
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  4. Renzo Ramelli
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  5. Andrea Manna
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Corresponding author

Correspondence to Michele Bianda.

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The authors declare that they have no conflicts of interest.

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Sunspot Number Recalibration

Guest Editors: F. Clette, E.W. Cliver, L. Lefèvre, J.M. Vaquero, and L. Svalgaard

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Cortesi, S., Cagnotti, M., Bianda, M. et al. Sunspot Observations and Counting at Specola Solare Ticinese in Locarno Since 1957. Sol Phys 291, 3075–3080 (2016). https://doi.org/10.1007/s11207-016-0872-7

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  • DOI: https://doi.org/10.1007/s11207-016-0872-7

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