Abraham Zacuto ( he, , translit=Avraham ben Shmuel Zacut, pt, Abraão ben Samuel Zacuto; 12 August 1452 – ) was a Castilian
astronomer
An astronomer is a scientist in the field of astronomy who focuses their studies on a specific question or field outside the scope of Earth. They observe astronomical objects such as stars, planets, natural satellite, moons, comets and galaxy, g ...
,
astrologer
Astrology is a range of divinatory practices, recognized as pseudoscientific since the 18th century, that claim to discern information about human affairs and terrestrial events by studying the apparent positions of celestial objects. Dif ...
,
mathematician
A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems.
Mathematicians are concerned with numbers, data, quantity, structure, space, models, and change.
History
On ...
,
rabbi
A rabbi () is a spiritual leader or religious teacher in Judaism. One becomes a rabbi by being ordained by another rabbi – known as ''semikha'' – following a course of study of Jewish history and texts such as the Talmud. The basic form of ...
and
historian
A historian is a person who studies and writes about the past and is regarded as an authority on it. Historians are concerned with the continuous, methodical narrative and research of past events as relating to the human race; as well as the stu ...
who served as Royal Astronomer to King
John II of Portugal
John II ( pt, João II; ; 3 March 1455 – 25 October 1495), called the Perfect Prince ( pt, o Príncipe Perfeito, link=no), was King of Portugal from 1481 until his death in 1495, and also for a brief time in 1477. He is known for re-establishi ...
copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
, his astronomical tables and maritime charts played an important role in the Spanish and Portuguese navigation capability. They were used by Vasco Da Gama and
Christopher Columbus
Christopher Columbus
* lij, Cristoffa C(or)ombo
* es, link=no, Cristóbal Colón
* pt, Cristóvão Colombo
* ca, Cristòfor (or )
* la, Christophorus Columbus. (; born between 25 August and 31 October 1451, died 20 May 1506) was a ...
.
The crater Zagut on the Moon is named after him.
Life
Zacuto was born in
Salamanca
Salamanca () is a city in western Spain and is the capital of the Province of Salamanca in the autonomous community of Castile and León. The city lies on several rolling hills by the Tormes River. Its Old City was declared a UNESCO World Heritag ...
astronomy
Astronomy () is a natural science that studies astronomical object, celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and chronology of the Universe, evolution. Objects of interest ...
at the
University of Salamanca
The University of Salamanca ( es, Universidad de Salamanca) is a Spanish higher education institution, located in the city of Salamanca, in the autonomous community of Castile and León. It was founded in 1218 by King Alfonso IX. It is th ...
. He later taught astronomy at the universities of
Zaragoza
Zaragoza, also known in English as Saragossa,''Encyclopædia Britannica'"Zaragoza (conventional Saragossa)" is the capital city of the Zaragoza Province and of the autonomous community of Aragon, Spain. It lies by the Ebro river and its tributari ...
and then
Carthage
Carthage was the capital city of Ancient Carthage, on the eastern side of the Lake of Tunis in what is now Tunisia. Carthage was one of the most important trading hubs of the Ancient Mediterranean and one of the most affluent cities of the classi ...
rabbi
A rabbi () is a spiritual leader or religious teacher in Judaism. One becomes a rabbi by being ordained by another rabbi – known as ''semikha'' – following a course of study of Jewish history and texts such as the Talmud. The basic form of ...
Alhambra Decree
The Alhambra Decree (also known as the Edict of Expulsion; Spanish: ''Decreto de la Alhambra'', ''Edicto de Granada'') was an edict issued on 31 March 1492, by the joint Catholic Monarchs of Spain ( Isabella I of Castile and Ferdinand II of Arag ...
ordering the expulsion of the Jews, Zacuto took refuge in
Lisbon
Lisbon (; pt, Lisboa ) is the capital and largest city of Portugal, with an estimated population of 544,851 within its administrative limits in an area of 100.05 km2. Grande Lisboa, Lisbon's urban area extends beyond the city's administr ...
,
Portugal
Portugal, officially the Portuguese Republic ( pt, República Portuguesa, links=yes ), is a country whose mainland is located on the Iberian Peninsula of Southwestern Europe, and whose territory also includes the Atlantic archipelagos of ...
. Already famous in academic circles, he was invited to court and nominated Royal Astronomer and Historian by King
John II of Portugal
John II ( pt, João II; ; 3 March 1455 – 25 October 1495), called the Perfect Prince ( pt, o Príncipe Perfeito, link=no), was King of Portugal from 1481 until his death in 1495, and also for a brief time in 1477. He is known for re-establishi ...
, a position which he held until the early reign of
Manuel I Manuel I may refer to:
* Manuel I Komnenos, Byzantine emperor (1143–1180)
*Manuel I of Trebizond, Emperor of Trebizond (1228–1263)
*Manuel I of Portugal
Manuel I (; 31 May 146913 December 1521), known as the Fortunate ( pt, O Venturoso), wa ...
. He was consulted by the king on the possibility of a sea route to
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
, a project which he supported and encouraged.
Zacuto would be one of the few who managed to flee Portugal during the forced conversions and prohibitions of departure that Manuel I enacted in order to keep the Jews in Portugal as nominal Christians for foreign policy reasons (see
persecution of Jews and Muslims by Manuel I of Portugal
On 5 December 1496, King Manuel I of Portugal signed the decree of expulsion of Jews and Muslims to take effect by the end of October of the next year.António José Saraiva: The Marrano Factory: The Portuguese Inquisition and Its New Christian ...
Jerusalem
Jerusalem (; he, יְרוּשָׁלַיִם ; ar, القُدس ) (combining the Biblical and common usage Arabic names); grc, Ἱερουσαλήμ/Ἰεροσόλυμα, Hierousalḗm/Hierosóluma; hy, Երուսաղեմ, Erusałēm. i ...
. He probably died in 1515 in Jerusalem; however, other reports indicate his final home was the Jewish community of
Damascus
)), is an adjective which means "spacious".
, motto =
, image_flag = Flag of Damascus.svg
, image_seal = Emblem of Damascus.svg
, seal_type = Seal
, map_caption =
, ...
and his death occurred in 1520. However, in a similar vein to other giants of the Jewish faith, such as
Saadia Gaon
Saʻadiah ben Yosef Gaon ( ar, سعيد بن يوسف الفيومي ''Saʻīd bin Yūsuf al-Fayyūmi''; he, סַעֲדְיָה בֶּן יוֹסֵף אַלְפַיּוּמִי גָּאוֹן ''Saʿăḏyāh ben Yōsēf al-Fayyūmī Gāʾōn''; ...
,
Maimonides
Musa ibn Maimon (1138–1204), commonly known as Maimonides (); la, Moses Maimonides and also referred to by the acronym Rambam ( he, רמב״ם), was a Sephardic Jewish philosopher who became one of the most prolific and influential Torah ...
and the Vilna Gaon, he followed the extremely old Jewish custom (believed to have begun in the
Babylonian captivity
The Babylonian captivity or Babylonian exile is the period in Jewish history during which a large number of Judeans from the ancient Kingdom of Judah were captives in Babylon, the capital city of the Neo-Babylonian Empire, following their defeat ...
) of being buried as close to Jerusalem as possible. Zacuto had established his wish to make his death pilgrimage at a Passover gathering.
Work
''Ha-ḥibbur ha-gadol''
Zacuto developed a new type of astrolabe, specialized for practical determination of
latitude
In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pol ...
while at sea, in contrast to earlier multipurpose devices intended for use ashore. Abraham Zacuto's principal claim to fame is the great astronomical treatise, written while he was in Salamanca, in
Hebrew
Hebrew (; ; ) is a Northwest Semitic language of the Afroasiatic language family. Historically, it is one of the spoken languages of the Israelites and their longest-surviving descendants, the Jews and Samaritans. It was largely preserved ...
, with the title ''Ha-ḥibbur ha-gadol'' ("The Great Book"), begun around 1470 and completed in 1478."Zacuto, Abraham" in Glick, T., S.J. Livesy and F. Williams, editors, (2005) ''Medieval science, technology, and medicine: an encyclopedia'', New York Routledge. It was composed of 65 detailed astronomical tables (
ephemerides
In astronomy and celestial navigation, an ephemeris (pl. ephemerides; ) is a book with tables that gives the trajectory of naturally occurring astronomical objects as well as artificial satellites in the sky, i.e., the position (and possibly ...
meridian
Meridian or a meridian line (from Latin ''meridies'' via Old French ''meridiane'', meaning “midday”) may refer to
Science
* Meridian (astronomy), imaginary circle in a plane perpendicular to the planes of the celestial equator and horizon
* ...
at Salamanca, charting the positions of the Sun, Moon and five planets. The calculations were based on the Alfonsine Tables and the works of earlier astronomers (notably of the 14th-century Majorcan school). Zacuto set out the data in a simple "almanac" format, with the positions of a planet easily interpolated between entries, making it quite easy to use.
The first Castilian translation was undertaken in 1481 by Juan de Salaya. Zacuto's Portuguese disciple Joseph Vizinus (Mestre
José Vizinho
José Vizinho, (also known in English as ''Joseph Vecinho''), was a Portuguese Jew, born in the town of Covilhã, court physician and scientist at the end of the fifteenth century.
He was a pupil of Abraham Zacuto, with whom he studied mathematic ...
, the much-valued physician and advisor of John II of Portugal) adapted it into a
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
translation, under the title ''Tabulae tabularum Celestium motuum sive Almanach perpetuum'' ("Book of Tables on the celestial motions or the Perpetual Almanac"), immediately along with a new Castilian translation, and arranged for its publication in 1496 by Samuel d'Ortas in Leiria, Portugal. (one of the first books published in Portugal with a movable type printing press).
''Biur luḥot''
Zacuto's ''Almanach perpetuum'' (or ''Biur luḥot'') helped immediately revolutionize ocean navigation. Prior to the ''Almanach'', navigators seeking to determine their position in the high seas had to correct for "compass error" (the deviation of the
magnetic north
The north magnetic pole, also known as the magnetic north pole, is a point on the surface of Earth's Northern Hemisphere at which the planet's magnetic field points vertically downward (in other words, if a magnetic compass needle is allowed t ...
from the
true north
True north (also called geodetic north or geographic north) is the direction along Earth's surface towards the geographic North Pole or True North Pole.
Geodetic north differs from ''magnetic'' north (the direction a compass points toward t ...
Pole Star
A pole star or polar star is a star, preferably bright, nearly aligned with the axis of a rotating astronomical body.
Currently, Earth's pole stars are Polaris (Alpha Ursae Minoris), a bright magnitude-2 star aligned approximately with its ...
. But this proved less useful as they approached the
equator
The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...
and the Pole Star began to disappear into the horizon. Zacuto's ''Almanach'' supplied the first accurate table of solar
declination
In astronomy, declination (abbreviated dec; symbol ''δ'') is one of the two angles that locate a point on the celestial sphere in the equatorial coordinate system, the other being hour angle. Declination's angle is measured north or south of the ...
, allowing navigators to use the sun instead. As the quadrant could not be used to look directly at the sun, Portuguese navigators began using the astrolabe on board (an old land-based instrument to measure the height of the sun indirectly). Zacuto's tables in conjunction with the new metal nautical astrolabe allowed navigators to take accurate readings anywhere. Already in 1497, Vasco da Gama took Zacuto's tables and the astrolabe with him on the maiden trip to India. It would continue to be used by Portuguese ships thereafter to reach far destinations such as
Brazil
Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
and
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
.
Vasco da Gama and his crew underwent a thorough briefing and preparation by Zacuto, in addition to learning to use the new instruments which he had developed for their trip before setting on the voyage to India in 1496. Prior to that, Zacuto had again improved on the existing astronomical tables, mostly those prepared under King Alphonso X of Castille. Already
Columbus
Columbus is a Latinized version of the Italian surname "''Colombo''". It most commonly refers to:
* Christopher Columbus (1451-1506), the Italian explorer
* Columbus, Ohio, capital of the U.S. state of Ohio
Columbus may also refer to:
Places ...
had used Zacuto's tables. The story is that on one of his voyages, when attacked by the natives, Columbus noted that Zacuto had predicted an eclipse for that day, and used this information to threaten the natives and convince them that he could extinguish the Sun and Moon and deprive them of all light. Zacuto's work thus saved the Admiral's life and that of his crew.
Other publications
In 1504, while in
Tunisia
)
, image_map = Tunisia location (orthographic projection).svg
, map_caption = Location of Tunisia in northern Africa
, image_map2 =
, capital = Tunis
, largest_city = capital
, ...
, Abraham Zacuto wrote a history of the Jewish people, ''Sefer yuḥasin'', since the Creation of the World until 1500, and several other astronomical/astrological treatises. The ''History'' was greatly respected and was reprinted in Cracow in 1581, at Amsterdam in 1717, and at Königsberg in 1857, while a complete, uncensored, edition was published by
Herschell Filipowski
Herschell E. Filipowski (1816 – 12 June 1872), also known as Tzvi Hirsh Filipowski (, ), was a Lithuanian-born British Jewish Hebraist, editor, mathematician, linguist and actuary.
Biography Early life
Herschell Filipowski was born in V ...
in London at 1857.
Legacy
Abraham Zacuto might have an uncredited appearance in
Luís de Camões
Luís Vaz de Camões (; sometimes rendered in English as Camoens or Camoëns, ; c. 1524 or 1525 – 10 June 1580) is considered Portugal's and the Portuguese language's greatest poet. His mastery of verse has been compared to that of Shakespear ...
's 1572 epic poem, ''
Os Lusíadas
''Os Lusíadas'' (), usually translated as ''The Lusiads'', is a Portuguese epic poem written by Luís Vaz de Camões ( – 1580) and first published in 1572. It is widely regarded as the most important work of Portuguese-language literature ...
Cassandra
Cassandra or Kassandra (; Ancient Greek: Κασσάνδρα, , also , and sometimes referred to as Alexandra) in Greek mythology was a Trojan priestess dedicated to the god Apollo and fated by him to utter true prophecies but never to be believe ...
-like character that surges 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). This may be Camões' poetic interpretation of an alleged meeting reported in
Gaspar Correia
Gaspar Correia (1492 – c. 1563 in Goa) was a Portuguese historian considered a Portuguese Polybius. He authored ''Lendas da Índia'' (Legends of India), one of the earliest and most important works about Portuguese rule in Asia.Belém beach just before his fleet's departure, in which Zacuto reportedly gave Gama some final navigational tips and warned him of dangers to avoid.
The small Abraham Zacuto Portuguese Jewish Museum ( pt, Museu Luso-Hebraico Abraão Zacuto)—founded in 1939 and located in the former
Synagogue of Tomar
The Synagogue of Tomar ( pt, Sinagoga de Tomar) is a well-preserved medieval synagogue in Tomar, Portugal. Along with the Synagogue of Castelo de Vide, it is one of two existing pre-expulsion synagogues in the country. It is located at 73 Rua Dr. ...
—is named after Zacuto.
Bibliography
* 1478, ''Ha-ḥibbur ha-gadol'' (''La Compilación Magna''), his first astronomical book, translated into Castilian 1481 by himself and Juan de Salaya from the University of Salamanca. In 1496 the work was translated into Latin translation by José Vizinho and published in Leira as ''Almanach Perpetuum'' or ''Tabule tabularum celestium motuum astronomi zacuti''. This work became important for the contemporary explorers.
* 1486, ''Tratado breve en las ynfluencias del cielo'', and ''De los eclipses del sol y la luna''.
* 1498, ''Sefer yuḥasin'', historical text for the Jewish people. Digital edition Zacuto, Avraham. ''Sefer yuḥasin''. Brooklyn, NY: Renaissance Hebraica, 1994. * 1498, astrological text predicting that the
Messiah
In Abrahamic religions, a messiah or messias (; ,
; ,
; ) is a saviour or liberator of a group of people. The concepts of ''mashiach'', messianism, and of a Messianic Age originated in Judaism, and in the Hebrew Bible, in which a ''mashiach'' ...
would come in 1503/4.
* after 1498, ''Mishpetei ha-'istagnin (Judgments of the astrologer)''