README for Sunspot Data Files The SIDC data files may be consulted and downloaded from two sites : A) ftp site : omaftp.oma.be, directory dist/astro/sidcdata HERE'S WHAT WE HAVE (CB) 4) monthssn.dat : monthly and monthly smoothed sunspot numbers from 1750 1st column : year and month 2d column : year and fraction of year (in julian years of 365.25 days) the reference date corresponds to the middle of the month 3d column : monthly sunspot number 4th column : monthly smoothed sunspot number R12=(R-6/2 +R-5+...+R+...+R5+R6/2)/12 -------------- ___________________________________________________________________________ | | | General remark : in all data files, the provisional sunspot numbers | | are marked by a *. | |___________________________________________________________________________| dist/astro/sidcdata also contains the graph files : - wolfjmms.png : daily sunspot number (yellow), monthly mean sunspot number (blue), monthly smoothed sunspot number (red) and predictions of the monthly smoothed suspot number for the last eleven years, up to now : SM (red dots) : classical prediction method, based on an interpolation of Waldmeier's standard curves; CM (red dashes) : combined method (due to K. Denkmayr), a regression technique coupling a dynamo-based estimator with Waldmeier's idea of standard curves. - wolfmms.png : monthly (blue) and monthly smoothed (red) sunspot numbers from 1954 up to now, showing then the present cycle (23) and the last four cycles. - wolfaml.png : annual (in black, up to 1750) then monthly smoothed (in red, up to the most recent one) sunspot numbers - wnosu.png : Monthly smoothed North (in blue) and South (in red) sunspot numbers. Sources : Royal Observatory of Belgium (up to 1991) - SIDC International Sunspot Number (from 1992) - papi22c.png : Maunder "butterfly" diagram for the past 22 years (full cycle), showing the the slow drift of the active regions on the disk from high to low latitudes during the solar cycle. B) All these files are also available on the site http://www.sidc.be updated September 12 2002