Sunspot data collection of Specola Solare Ticinese in Locarno

Sunspot observations and counting are carried out at the Specola Solare Ticinese in Locarno since 1957 when it was built as an external observing station of the Zurich observatory. When in 1980 the data center responsibility was transferred from ETH Zurich to the Royal Observatory of Belgium in Brussels, the observations in Locarno continued and Specola Solare Ticinese got the role of pilot station. The data collected at Specola cover now the last 6 solar cycles.

The aim of this presentation is to discuss and give an overview about the Specola data collection, the applied counting method and the future archiving projects. The latter includes the publication of all data and drawings in digital form in collaboration with the ETH Zurich University Archives, where a parallel digitization project is ongoing for the document of the former Swiss Federal Observatory in Zurich collected since the time of Rudolph Wolf.