Josef (also José or Joseph) de Mendoza y Ríos (1761–1816) was a Spanish astronomer and mathematician of the 18th century, famous for his work on navigation. The first work of Mendoza y Ríos was published in 1787: his treatise about the science and technique of navigation in two tomes. He also published several tables for facilitating the calculations of nautical astronomy and useful in navigation to calculate the latitude of a ship at sea from two altitudes of the sun, and the longitude from the distances of the moon from a celestial body. In the field of the nautical instruments, he improved the reflecting circle. In 1816, he was elected a foreign member of the Royal Swedish Academy of Sciences.

Biography

In 1787, De Mendoza published his first work, his treatise on the sciences and techniques of navigation in two volumes, a reference work of the time. After this, he proposed the creation of the maritime library, located in Cádiz, which would eventually become the Depósito Hidrográfico of the navy. He also published several tables using the harversine method (of his invention), to facilitate the calculations of nautical astronomy and navigation. Mainly oriented to the calculation of the latitude of a ship at sea by means of two heights of the Sun and the time elapsed between them, and to the obtaining of the longitude by the method of lunar distances. In the field of nautical instruments, he perfected the reflecting circle of Borda. In 1816, he was elected a foreign member of the Royal Swedish Academy of Sciences. As a curious fact about the method of calculation of that time, while writing the last edition of his famous Lunar Tables, in 1815 (ten months before he died drowned in Brighton), he wrote a letter to general Espinosa y Tello (a good friend of him), where he said verbatim: "... I have at hand Works of such magnitude that two calculators cannot cope, I will take four or five more calculators on my return to London ... "

His work

Honors

Mendoza Cove in Antarctica is named after José de Mendoza y Ríos.