A "lost" sunspot observation in 1785

Vaquero J.M., Trigo R.M., Gallego M.C.
AstronomischeNachricht . 326, 112-114.

Download PDF


The reconstruction of the solar activity during some years of the 18th century is poorly known because there are scarce sunspot observations. The aim of this short contribution is to present a "lost" sunspot observation realized by the Portuguese scientist Sanches Dorta during his observation of the solar eclipse of 1785 from Rio de Janeiro (Brazil). This record was not included in the database compiled by Hoyt and Schatten (1998). We present new estimations of the solar activity during 1785.