SSN-Workshop Wiki
Sunspot group

Welcome to the Wiki of the Sunspot Number Workshops.

Here you'll find the latest information about the meetings.

Why the Sunspot Number Needs Re-examination

The SSN workshops are sponsored by the National Solar Observatory (NSO), the Royal Observatory of Belgium (ROB), and the Air Force Research Laboratory (AFRL). We are happy to report that Frédéric Clette of ROB has joined Leif and Ed as a Co-Organizer of the SSN Workshop Series. We view the September 2011 workshop as the first step in an effort to provide the solar community with a vetted long-term (single) sunspot number and the tools to keep it on track. This will take a lot of work and we look forward to collaborating with each of you. We held a second workshop at ROB on Brussels in May 2012 (and a third one at NSO in Tucson in January 2013, and hopefully one somewhere in Europe in 2014) and are considering a special Topical Issue of Solar Physics for the eventual joint publication of the SSN series and the accompanying historical, procedural, and scientific papers.

Sincerely yours, Ed, Frédéric, & Leif.

1st SSN Workshop September, 2011

2nd SSN Workshop May, 2012

Mini SSN Workshop September, 2012

3rd SSN Workshop January, 2013

4th SSN Workshop May, 2014

1st ISSI Workshop May, 2012 (Long-term Reconstruction of Solar and Solar Wind Parameters)

[1]Recalibration of Sunspot Series - Staus Report:

Website Address:

Stay tuned to this site for further announcements or updates. Leif is the curator for the website so please contact him with any questions or suggestions (

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