The SIDC data files may be consulted and downloaded from two sites : A) ftp site : omaftp.oma.be, directory dist/astro/sidcdata 1) mai1xxzz.dat : text of the e-mail message of the 1st of the month, relative to the provisional sunspot number of the elapsed month and the predictions (xx nø of the month, zz last two figures of the year) 2) mai2xxzz.dat : text of the e-mail message of the 1st of the month, relative to the provisional hemispheric sunspot numbers. 3) dayssn.dat : daily sunspot numbers from 1812 1st column : year, month and day 2d column : year and fraction of year (in julian years of 365.25 days) 3d column : sunspot number Important remark : this file is a long file. To avoid difficulties due to its length, please consult the sub-directory dailyssn, which contains individual yearly files dssn????.dat (???? = year) of the daily sunspot number (same presentation as dayssn.dat). The files dssn1992.dat and following also contains the SIDC daily North and South sunspot numbers, in column 4 and 5. 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 5) yearssn.dat : yearly sunspot number, from 1700 1st column : year 2d column : sunspot number 6) monssnns.dat : monthly and monthly smoothed North and South Sunspot numbers, from 1992. 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 North sunspot number 4th column : monthly South sunspot number 5th column : monthly North smoothed sunspot number 6th column : monthly South smoothed sunspot number ___________________________________________________________________________ | | | 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