His astrolabe of copper, astronomical tables, and maritime charts played an important role in the Spanish and Portuguese voyages of discovery, being used by both Vasco Da Gama and Christopher Columbus.

[4] With the Catholic Monarchs of Spain issuing the 1492 Alhambra Decree ordering the expulsion of the Jews, Zacuto took refuge in Lisbon, Portugal.

Already famous in academic circles, he was invited to court and nominated Royal Astronomer and Historian by King John II of Portugal, a position which he held until the early reign of Manuel I.

[citation needed] Abraham Zacuto developed a new type of astrolabe, specialised for practical determination of latitude while at sea, in contrast to earlier multi-purpose devices intended for use ashore.

[5] It was composed of 65 detailed astronomical tables (ephemerides), with radix set for the year 1473 and with the meridian at Salamanca, charting the positions of the Sun, Moon and five planets.

[5] Zacuto's Portuguese disciple Joseph Vizinus (Mestre José Vizinho, the much-valued physician and advisor of John II of Portugal) translated it into Latin, under the title Tabulae tabularum Celestium motuum sive Almanach perpetuum ("Book of Tables on the celestial motions or the Perpetual Almanac"), along with a new Castilian translation, and arranged for its publication in 1496 by Samuel d'Ortas in Leiria, Portugal.

[9] In 1504, while in Tunisia, Abraham Zacuto wrote a history of the Jewish people, Sefer yuḥasin, starting with the Creation of the World and going to 1500,[10][11] and several other astronomical/astrological treatises.

The History was highly regarded and was reprinted in Cracow in 1581, in Amsterdam in 1717, and in Königsberg in 1857, while a complete, uncensored,[12] edition was published by Herschell Filipowski in London in 1857.

[13] Abraham Zacuto might have an uncredited appearance in Luís de Camões's 1572 epic poem, Os Lusíadas, as "the Old Man of Restelo", a Cassandra-like character that comes forward just before Vasco da Gama's departure to chide the vanity of fame and warn of the travails that await him (Canto IV, v.94-111).