Use this form to access the American Relative Sunspot Number (Ra) as published by the National Geophysical Data Center (which is shut down pending a Federal budget agreement). These numbers reflect what was published by NGDC, and may contain typographical errors. For the official AAVSO value of Ra, see the AAVSO Solar Bulletin for specific month(s) you are interested in.
American Relative Sunspot Number
The AAVSO Solar Section has been actively improving its data collection and analysis methods over the past year. We've gotten critically important feedback from the global solar research community on the importance of amateur observations of sunspots, and the AAVSO Solar Section is building new and stronger relationships with the professional community. We've never been in a better position to support both the solar observers and the researchers that critically depend upon your data, and we're looking to make even more improvements in the near fut