Abstract
Daily relative sunspot numbers are based upon counts of spots and group entities of spots on the sun’s surface at some time each day. Wolf devised a relative number with the intent of reducing the spot counts of different observers and telescopes to a common basis. The relative number is k(f + 10g) where, for a given day, g is the number of groups, irrespective of the number of component spots, f is the total number of component spots which can be counted in these groups and may range from 1 to 50 or more in the case of complex groups, and k is a scale factor depending on the estimated efficiency of the observer and his telescope. The daily sunspot numbers are evaluated on the basis of more than fifty observing stations around the world and related to the observations of a reference station (which changed in 1982). The series provided, Table 11.1, is that of the simple mean of the daily values for each month.
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