SILSO

SILSO (Sunspot Index and Long-term Solar Observations) is a scientific organization dedicated to the continuous monitoring and analysis of solar activity, particularly focusing on sunspots. Operated by the Royal Observatory of Belgium, SILSO collects and maintains data on the number and distribution of sunspots on the solar surface, which serve as key indicators of solar activity and variability.

Established in 2004, SILSO’s primary role is to coordinate global efforts in observing sunspots and providing standardized indices for solar activity. The organization compiles daily sunspot numbers and creates long-term datasets that are essential for understanding solar cycles, which typically last about 11 years. These datasets are used in research related to space weather, climate studies, and the Sun’s influence on the Earth's environment.

SILSO publishes the international Sunspot Number, also known as the Zurich or Wolf Sunspot Number, which is one of the longest-running solar activity indices. This index is derived from a combination of counts of individual sunspots and groups of sunspots observed on the solar disk. The organization also collaborates with observatories worldwide to ensure data consistency, accuracy, and to facilitate the exchange of solar observation techniques.

Research conducted by SILSO contributes to our understanding of the solar cycle’s patterns and potential impacts on satellite operations, communications, and power systems on Earth. Data provided by SILSO supports space weather forecasting and advances in heliophysics.

Overall, SILSO plays a vital role in solar monitoring and contributes valuable data to the global scientific community, aiding in the prediction of solar phenomena and their terrestrial effects.