News 001: Welcome to the new central Web site for the International Sunspot...
Welcome to the new central Web site for the International Sunspot Number !We designed those new Web pages to offer you an easier access to the existing sunspot data and to the associated information....
View ArticleNews 002: From SIDC to SILSO, why a new name?
Over the past month, we already got very positive feedback about our new Web site. Like for all new Web sites, we had to fix a few initial defects but now, the web site seems to be on its tracks. Sorry...
View ArticleThe SILSO upgrade continues: new prediction files and plots
Over past weeks, various upgrades took place in the backstage. We further improved the primary scripts for the sunspot number calculation. We also improved the internal data flow. The biggest...
View Article2014 : maximum year for solar cycle 24
Now that we completed the definitive sunspot numbers for 2014, we can conclude that the maximum of solar cycle 24 was reached in April 2014, with a maximum of the 13-month smoothed sunspot number at...
View ArticleMajor change of data set on July 1st, 2015
Over the past 4 years a community effort has been carried out to revise entirely the historical sunspot number series. A good overview of the analyses and identified corrections is provided in the...
View ArticleAdvancing towards the July 1st transition: no change for our observers
The preparation of the July 1st transition is progressing at high pace. Hundreds of lines of codes are adapted for the new sunspot number series and for the new array of data files. The corrections can...
View ArticleNew Data pages with archive of past versions
After completing the new data files themselves, we are now finalizing the design of the new sections in our data pages. Indeed, although the new Sunspot Number will bring large improvements to the most...
View ArticleTransition to the new Sunspot Number successfully completed
Today marked a triple transition for us: - Uploading the new Sunspot Number archive files containing the daily, monthly and yearly re-calibrated sunspot numbers and the new Group Number series - In our...
View ArticleNew 'Spotless days' page
Regular solar observers have noticed that since mid-2016, the Sun has occasionally been devoid of sunspots. As the current solar cycle 24 will gradually give way to the new solar cycle 25, several...
View ArticleNew prediction method
Starting from a collaboration with the NCEI (NOAA, Boulder USA), we implemented new 12-month ahead predictions based on the McNish and Lincoln method. This rather simple method is based on a single...
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Solar Cycle 25
An international panel of experts coordinated by the NOAA and NASA,to which the WDC-SILSO contributed, released a preliminary forecast for Solar Cycle 25 on April 5, 2019. Based on a compilation of...
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Solar cycle minimum passed in December 2019
In January 2020, the 13-month smoothed sunspot number rose for the first time since the maximum of cycle 24 (April 2014). Most probably, this indicates that the minimum between cycles 24 and 25 was...
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The new solar activity cycle.
December 2019 confirmed as starting point of the new solar activity cycleDecember 2019 door Belgische wetenschappers bevestigd als start van de nieuwe zonnecyclusDes scientifiques belges confirment que...
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