World Data Center for the production, preservation and dissemination of the international sunspot number


Sunspot number series: latest update

Daily estimated sunspot number
06 December : 33
07 December : 19
08 December : 14
09 December : 20
10 December : 0

Transition 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 Web site, switching to the new "Data" pages giving access to the new files, to updated graphics and also to the past version of the Sunspot Number
- Adapting and running the entire monthly procedure to produce the provisional Sunspot Numbers for June 2015 and the associated 12-months forecast and EISN.
Thus a lot of work in a single day for our small team.

After intensive verifications and some inevitable bugs, we have now successfully completed this transition. The new numbers for June seamlessly extend the recalibrated historical sunspot series. Except for the announced elimination of the 0.6 conventional factor, absolutely no tweaking of the data was done. We simply kept the Specola Observatory (Locarno) as pilot station but now using... more

Wed, 01 Jul 2015
Latest USET observations (ROB, Brussels) 09/12/2016

Latest USET drawing

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