A COMPARISON OF WOLF RECONSTRUCTED RECORD OF ANNUAL SUNSPOT NUMBER WITH SCHWABE OBSERVED RECORD OF CLUSTERS OF SPOTS FOR THE INTERVAL OF 1826-1868

Samuel Heinrich Schwabe, the discoverer of the sunspot cycle, observed the Sun routinely from Dessau, Germany during the interval of 1826-18 68, averaging about 290 observing days per year. His yearly counts of 'clusters of spots' (or, more correctly, the yearly number of newly ap pearing sunspot groups) provided a simple means for describing the ove rt features of the sunspot cycle (i.e., the timing and relative streng ths of cycle minimum and maximum). In 1848, Rudolf Wolf, a Swiss astro nomer, having become aware of Schwabe's discovery, introduced his now familiar 'relative sunspot number' and established an international ca dre of observers for monitoring the future behavior of the sunspot cyc le and for reconstructing its past behavior (backwards in time to 1818 , based on daily sunspot number estimates). While Wolf's reconstructio n is complete (without gaps) only from 1849 (hence, the beginning of t he modern era), the immediately preceding interval of 1818-1848 is inc omplete, being based on an average of 260 observing days per year. In this investigation, Wolf's reconstructed record of annual sunspot numb er is compared against Schwabe's actual observing record of yearly cou nts of clusters of spots. The comparison suggests that Wolf may have m isplaced (by about 1-2 yr) and underestimated (by about 16 units of su nspot number) the maximum amplitude for cycle 7. If true, then, cycle '7's ascent and descent durations should measure about 5 years each in stead of 7 and 3 years, respectively, the extremes of the distribution s, and its maximum amplitude should measure about 86 instead of 70. Th is study also indicates that cycle 9's maximum amplitude is more relia bly determined than cycle 8's and that both appear to be of comparable size (about 130 units of sunspot number) rather than being significan tly different. Therefore, caution is urged against the indiscriminate use of the pre-modern era sunspot numbers in long-term studies of the sunspot cycle, since such use may lead to specious results.