Analysis of Sun-spot Records in the Chinese annals
Cheng Ting fang
109 records of snn-spots have been collected from the chinese annals,covering the period from Former Han Dynasty (43 B. C.) to the end of Ming(1638 A. D.). 3 sunspots were recorded in two places,so there are actuallyrecords of only 106 separate spots or spot groups. The original texts are givenin the table, together with the dates, both according to the ancient Chinesecalendar and according to Gregorian calendar. In the annals, records of meteorological phenomena often appeared sideby side with those of sunspots. Sun-spots were named "dark gas" or "darkspot" by ancient Chinese astronomers. They described the forms and sizes ofsun-spots in the following way:as large as a bullet, as a coin, as an egg,or as an apple, shaped like a bird, like a person etc. Some Sun-Spots wereseen for as long as 30 days. Many were visible for more than 10 days,so theymight be one or more than one large group of naked eye sun-spots. In 1889 the Japanese astronomer S. Hirayama collected 95 records in atable which was publid in "The Observatory" volume 12,1889. Jsing thistable H. H. Turner found a mean sun-spot period of 11.06 or 10.54 years,and estimated the maximum years to be 189, 300, 875, 975, 1074, 1118,……, 1616, 1627, 1638.A.D. Although we are not sure that exceptionally large sun-spots always appearat the time of sun-spot maximum, it can safely be assumed that naked eyesun-spots often appear in the maximum year or the year before or the yearafter. If more than one naked eye sun-spots appeared at the same time, ormore than one naked eye sun-spot appeared in one year, then that yearmust be the maximum year. If there are naked eye sun-spots appeared in twosuccessive years, one of them must be the year of sun-spot maximum. More- over, if an exceptionally large sun-spot appeared in a certain year,it is veryprobable that it is a maximum year. According to the above discussion andthe data collected, we conclude that besides the sun-spot maximum yearswhich Turner has deduced,the following years are probably also maximumyears: C., 28 B.C, 311, 322, 342, 355, 375, 388, 400, 501, 511,567, 578, 826, 837, 1079, 1112, 1130, 1138, 1160, 1186, 1193, 1203.1371, 1382. There are more records of sun-spots in 4th, 12th and 14th centuries. Thismay be due to political reasons,or due to some inherent property of sun-spots.If it is due to the latter reason, then sun-spots activity has besides the 11yearsperiod a long period of 800--1000 years,like the period of light variations ofa semi-regular variable star.