Solar Calcium Plages

Solar observatories monitor the Sun in the calcium (Ca) K line wavelength by using a filter that allows only this wavelength's light through, calcium filtergrams, or spectroheliograms. Daily full disk calcium K232 images are reduced to provide calcium plage positions and areas or summed to produce a daily Ca K index. Ca K active regions can be seen moving across the solar disk, above the white light sunspot regions, and higher in the solar atmosphere (chromosphere).

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Calcium Data

• Daily Calcium Plage Areas from Mt. Wilson Observatory 1915-1984 -- Peter Foukal
• San Fernando Observatory K-line facular data -- Gary Chapman
  1988-1998 -- daily areas and irradiance indices, such as the excess spectral irradiance in the K line 393.4 nm (ASCII)
• Daily calcium plage reduced data, including position, areas and intensities
  
  
• Hale Observatory (Mt. Wilson Solar Observatory -- Oct 1979-Sep 1981):
  
  Data Documentation

  Download Data: Choose Year 1981 1980 1979
• Mt. Wilson Solar Observatory:
  
  Data Documentation

  Download Data: Choose Year 1984 1983 1982 1981 1980 1979 1978 1977 1976 1975 1974 1973 1972 1971 1970 1969 1968 1967 1966 1965 1964 1963 1962 1961 1960 1959 1958 1957 1956 1955 1954 1953 1952 1951 1950 1949 1948 1947 1946 1945 1944 1943 1942 1941 1940 1939 1938 1937 1936 1935 1934 1933 1932 1931 1930 1929 1928 1927 1926 1925 1924 1923 1922 1921 1920 1919 1918 1917 1916 1915
• McMath Solar Observatory:
  
  Data Documentation

  Download Data: Choose Year 1979 1978 1977 1976 1975 1974 1973 1972 1971 1970 1969 1968 1967 1966 1965 1964 1963 1962 1961 1960 1959 1958 1957 1956 1955 1954 1953 1952 1951 1950 1949 1948 1947 1946 1945 1944 1943 1942
• Big Bear Solar Observatory:
  
  Data Documentation

  Download Data: Choose Year 1987 1986 1985 1984 1983 1982 1981

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Calcium K index

Daily summary data -- includes YYMMDD, number of plage regions, total corrected plage area, and Calcium plage index

• Big Bear Solar Observatory:
  
  Data Documentation

  Download Data: Choose Year 1987 1986 1985 1984 1983 1982 1981
• McMath Solar Observatory:
  
  Data Documentation

  Download Data: Choose Year 1987 1986 1985 1984 1983 1982 1981 1980 1979 1978 1977 1976 1975 1974 1973 1972 1971 1970 1969 1968 1967 1966 1965 1964 1963 1962 1961 1960 1959 1958 1957 1956 1955 1954 1953 1952 1951 1950 1949 1948 1947 1946 1945 1944 1943 1942
• Sacramento Peak Solar Observatory:
  
  Data Documentation

  Download Data: Choose Year 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 1986 1985 1984 1983 1982 1981 1980 1979 1978 1977 1976

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SGD Tables

• Solar-Geophysical Data Regions of Solar Activity Table 1969-1982 (Documentation)
• Daily white light sunspot regions are tied to the overlying Ca K plage regions each day.

Download Data: Choose Year 1982 1981 1980 1979 1978 1977 1976 1975 1974 1973 1972 1971 1970 1969