2017/06/05 - 1) Database corrections to date/time for 1982-present. Previous date/times were off by a half a day. Times were changed from 0.500 days to 0.000 days and dates were incremented by one day. 2) Columns 26-29 now contain the Zurich/McIntosh sunspot group classifications (instead of zeros for lack of umbral area information). 3) Columns 36-39 now contain the number of sunspots in the group (instead of zeros for lack of umbral area information). The revised format is contained in the format.txt file
2017/05/06 - This database was relocated from the NASA/Marshall Solar Physics
website to this Solar Cycle Science
2012/08/02 - Yearly data files g2005.txt, g2006.txt, g2007.txt, and g2008.txt have been rewritten to correct a formatting error caught by Andrey Tlatov.
2012/04/02 - This database saw significant revisions. Over 120 days in which sunspots should have been observed do not have records and are now noted as missing days through the inclusion of records with year, month, and day but all other columns zeroed out in the raw data files (gYYYY.txt). The missing days are also enumerated in a file: MissingDays.txt
. Accounting for these missing days, as well as the variation between 27 and 28 days in a Carrington Rotation, has also slightly changed the monthly sunspot area calculations and the values used in making the Butterfly diagram.
2012/04/02 - Another change is the deletion of data on sunspot umbral areas from 1977 to 1981. It is now clear that these numbers were fabricated using a model for the ratio of the umbral area to the whole spot area that has significant flaws. Also, Giuliana de Toma noted that the corrected and uncorrected whole spot areas were in disagreement starting in 1982. Starting in 1982 the corrected areas were the primary data and the uncorrected areas were calculated using the sunspot group distance from disk center. These values are now properly calculated. Please note that, as before, the data in the raw data files (gYYYY.txt) are uncorrected for the change in data source in 1977. The derived data (daily_area.txt, sunspot_area.txt, sunspot_area_north.txt, sunspot_area_south.txt, and bflydata.txt) do include the correction factor of 1.4x after 1976/12/31.