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Osservatorio astronomico della Specola Solare

The Specola Solare Ticinese started the activity in 1957 as a station of the ETH Zurich Observatory. From the beginning, the research focused on the observation of the solar photospheric activity and in particular on the detemination of the international index called Wolf number, now Sunspot Number (SSN).

Since 1981 ETH did not include the solar activity determination in its scientific program anymore and it renounced to continue the operation of the Observatory. The determination of the Sunspot Number was token over by the “Sunspot Index Data Center” (SIDC) now Sunspot Index and Long-term Solar Observations (SILSO) in Brussels. The continuation of the operation of the Specola Solare Ticinese was guaranteed by a local association called Associazione Specola Solare Ticinese (ASST), which was founded for that purpose.

At present the main scientific goal of the Specola is still the determination of the Sunspot Number. The data collected at the Specola are sent regularly to the SILSO, where the Specola is considered the pilot station.

Specola Solare – Locarno Monti


  • A Zeiss refractor (150 mm opening) in an hemispheric dome (used for the sunspot drawings)
  • Coelostat (200 mm) and a refractor (140 mm) followed by an optical bench with spectrographs and monochromatic filters

For night observations the following instrument is also available:

  • Maksutov-Cassegrain refractor D=300 mm F=4800 mm


IndirizzoSpecola Solare Ticinese
Via ai Monti 146
6605 Locarno Monti
Telefono+41 91 290 90 34 (lu-ve, 9-11.30)
Coordinate46.172336 / 8.787919