References to halley's comet from the cadiz observatory

Abstract

This paper presents the history of the observations of Halley's comet, in its first scheduled appearance, which were made from the Observatory of Cádiz. A history that links Cadiz with important names: Edmund Halley, who went to Isaac Newton to check the comet's orbit; Jorge Juan and the creation of the Cadiz Observatory which his friend Luis Godin would direct; important astronomers such as Joseph-Nicolas Delisle, who talked to Halley in London and was interested in his predictions, and his disciple the astronomer Charles Messier, who was nicknamed the comet hunter, due to the number of comets he described. Godin, who was himself a fellow astronomy student of Delisle, tracked Halley's comet from the Cadiz observatory, and it is recorded that these observations were taken and sent to Delisle. At a time when data collection was manual, as was the copying of the data and the corresponding annotations; and at a time when the transfer of information was not like e-mails, but was done by horse-drawn carriage, the guarantee that this information reached so many kilometres away could only be given in a later publication. That ratification is the one presented in this article, which completes the link between the Observatory of Cádiz and Halley's comet.