WDC Sunspot Index and Long-term Solar Observations
Also known as SILSO
SILSO is the World Data Center for the production, preservation and dissemination of the international sunspot number.
Getting access
Open access Open
- How to apply
- Not yet verified — we don’t publish a route we haven’t checked.
Summarised from a registry — the exact application route is not yet verified.
About this database
| Website | https://www.sidc.be/SILSO/home |
|---|---|
| Subjects | Natural Sciences · Physics · Geosciences (including Geography) · Astrophysics and Astronomy · Atmospheric Science and Oceanography · Atmospheric Science |
| Last updated | 2026-09-13 |