On the solar activity during the year 1784

The solar observations performed by the Mexican astronomer J. A. Alzate during the year 1784 are analysed in this work. These observations are very valuable for the reconstruction of solar activity because Hoyt and Schatten (1998), who defined the Group Sunspot Number (R _G), only found five observations during this year — all performed by J. C. Staudacher. Using conjointly the data provided by Alzate and Staudacher for 1784, one can determine a value of R _G equal to 0.3±0.1 with eighty records for that year.