Extraído de:http://www.zacuto.com/rabbi.htm
Abraham ben Samuel Zacuto & Vasco de Gama
No single person in Portugal, apart from those who sailed with Vasco da Gama, was more intimately associated with the expedition that discovered Natal and the sea route to India by way of the Cape then the Jew, Abraham Zacuto. The advice of Zacuto was indispensable to Manuel’s maritime projects, and his instructions materially assisted the great explorer in at least one difficult situation. The expedition, indeed, was only undertaken after grave consultation by the King of his Astronomer Royal, Zacuto.
Abraham ben Samuel Zacuto was renowned as a teacher of astronomy and mathematics at the University of Salamanca, then the greatest seat of learning in the world. He was the author of Ephemerides, of other works on astronomy, and of chronological history of the Jews from the creation to 1500, containing critical references to Jewish literature in every period, entitled Sepher-ha-Yuchasin. He had prepared, about 1473, a set of astronomical tables showing the declination of the sun, which enabled mariners to determine their latitude, when the pole-star was invisible, by calculating the altitude of the sun. Even before the time of Vasco da Gama’s first voyage, these tables were widely used by navigators In fact, there is very little doubt that Bartholomeu Diaz used them when he first rounded the Cape of Storms in 1487. It is certain that Christopher Columbus was never without them. They accompanied him to the New World, and his personal copy, with his autograph notes in it, is still preserved in the Columbina at Seville. These famous tables were first published in Hebrew, and were translated into Latin and Spanish later by Joseph Vecinho. The Latin version, printed at Leiria by a Jewish printer in 1496, bore the title, Almanach perpetuum Celestium motuum cujus radix est 1473.
When the fateful edict of expulsion was issud against the Spanish Jews in 1492, Abraham Zacuto fled to Portugal. His aged master, the pious and learned Rabbi Isaac Aboab fled to Oporto, where Zacuto followed him, but the venerable Rabbi died within a few months of leaving his native land. Zacuto pronounced the funeral oration over his dead master and left Oporto to settle in Lisbon. Here he was soon received with favor by the King, who realized the value of his learning. In 1495 Joao II died, and Manuel II, who succeeded him, appointed Abraham Zacuto Astronomer Royal and showed him every mark of esteem. Manuel interested himself in navigation, and frequently summoned the Astronomer to Beg to discuss that science with him. In particular was attracted by the theory of storms that Zacuto had advanced. There were frequent and weighty conferences with Zacuto when Vasco da Gama’s fleet was about to be dispatched. The Admiral put himself under the special tuition of Zacuto, who advised and instructed him as well as made himself responsible for the selection for the Admiral’s scientific equipment of instruments, maps and documents, and general sailing instructions. Da Gama was provided with a copy of Zacuto’s tables, a large wooden astrolabe, smaller and more convenient ones of iron and brass specially invented for him by Zacuto, and other nautical instruments.
Amongst the documents that might assist him with information about the unknown seas into which he was going was a copy of the letter brought to Portugal about 1487 by the Jewish travelers, Rabbi Abraham of Beja and Joseph Zapateiro de Lamego, conveying the first definite information that it was possible to sail around the Southern coast of Africa into the Indian Ocean and so to India.
On the great day when the fleet was to sail, by Manuel’s special orders, Zacuto, in a private conference with da Gama, solemnly imparted to him final advice for the conduct of the expedition. The astronomer also held official converse with him in the presence of the crews and the waiting crowds at the moment of departure for the sailing was conducted with grave ceremony, to the accompaniment of religious processions and a vast crowd of onlookers chanting a litany.
Zacuto lived to see the triumphant return of his illustrious pupil, and the departure of succeeding fleets for the East Cabral, Joao de Nova and Albuquerque all carried manuscript copies of his Almanac. He died in 1510.
The Sea Route To India
India would be found, and for the purpose of determining the best means he set up a Commission of specialists on maritime matters, consisting of five experts. Besides the Bishop of Ceuta, Martim Behaim the Nuremberg cosmographer, and Rodrigo the court physician, there were Joseph Vecinho the Jewish astronomer and Moses the mathematician. It was to this Commission that King joao referred Columbus’ scheme for finding Cathay by sailing west, and Columbus complained that it was the "Jew Joseph" who had rejected his proposals. Columbus records in his notes that the King sent his physician and this same "astrologer", Joseph Vecinho, to measure the altitude of the sun throughout Guinea, and that the Jew gave an account to the King of his mission, Columbus’s brother Bartholomeu being present. Vecinho’s teacher had been the famous professor of astronomy, Abraham Zacuto. It was under jodo II. That Bartholomeu Diaz set out on that voyage which resulted in the discovery of the Cape of Good Hope. The accounts of it are very scanty, for Diaz did not receive the honors that fell to his more fortunate countryman, Vasco da Gama, whose achievement was the crowning event of a long series. Consequently there is no record of Jews having participated in it directly, though they may very well have been amongst his crews as they were in those of da Gama and Columbus. Joseph Vecinho, the astronomer and Moses the mathematician, indeed, being of the Commission of five under whose management jodo II. Had organized exploration, had some hand it its preparation, and it is not unlikely that Diaz carried as did his successors, a Jewish interpreter and was equipped by Jewish scientists; but these can never be more than matter of speculation. About the same time, however, King jodo dispatched another expedition, the result of which was of not less importance than that of Diaz. With this second expedition Jews were intimately connected…
Whiteways, in "The Rise of Portuguese Power in India", remarks on the frequency with which missions which entailed hazardous overland journeys in the fifteenth and sixteenth centuries were entrusted to Jews, especially by the rulers of the Portuguese Indian Empire. "During the fifteenth and sixteenth centuries the Jews were the great land travelers - the references to them are continual
1 A History of the Jews of South Africa; P. 19 - 21 Louis Herrman London, Victor Gollancz 1930.