乔凡尼·多美尼科·卡西尼

Giovanni Domenico Cassini (8-11 June 1625 – 14 September 1712) was an Italian-French mathematician, astronomer, astrologer and engineer. Cassini was born in Perinaldo, near Imperia, at that time in the County of Nice, part of the Savoyard state. He discovered four satellites of Saturn and noted the division of its rings, later named the Cassini Division. Cassini was also the first of his family to begin work on the project of creating a topographic map of France. In addition, he also created the first scientific map of the Moon.

The Cassini space probe, launched in 1997, was named after him and became the fourth to visit Saturn and the first to orbit it.

Life

Time in Italy

Cassini was the son of Jacopo Cassini, a Tuscan, and Giulia Crovesi. In 1648 Cassini accepted a position at the observatory at Panzano (Castelfranco Emilia), near Bologna, to work with Marquis Cornelio Malvasia, a rich amateur astronomer, initiating the first part of his career. During his time at the Panzano Observatory, Cassini was able to complete his education under the scientists Giovanni Battista Riccioli and Francesco Maria Grimaldi. In 1650 the senate of Bologna appointed him as the principal chair of astronomy at the University of Bologna.

While in his position in Bologna, he observed and wrote a book on the comet of 1652.……

Moving to France

Cassini's determinations of the rotational periods of Jupiter and Mars in 1665–1667 enhanced his fame, and in 1669, with the reluctant assent of the Pope, he moved to France and through a grant from Louis XIV, the "Sun King" of France, helped to set up the Paris Observatory, which opened in 1671;……

Astronomer

Cassini observed and published surface markings on Mars (earlier seen by Christiaan Huygens but not published), determined the rotation periods of Mars and Jupiter, and discovered four satellites of Saturn: Iapetus and Rhea in 1671 and 1672, and Tethys and Dione (1684). Cassini was the first to observe these four moons, which he called Sidera Lodoicea (the stars of Louis), including Iapetus, whose anomalous variations in brightness he correctly ascribed as being due to the presence of dark material on one hemisphere (now called Cassini Regio in his honour). In addition, he discovered the Cassini Division in the rings of Saturn in 1675.……

Astrologer

Attracted to the heavens in his youth, his first interest was in astrology. While young he read widely on the subject, and soon was very knowledgeable about it; this extensive knowledge of astrology led to his first appointment as an astronomer. Later in life he focused almost exclusively on astronomy and all but denounced astrology as he became increasingly involved in the Scientific Revolution.

In 1645 the Marquis Cornelio Malvasia, a senator of Bologna with a great interest in astrology, invited Cassini to Bologna and offered him a position in the Panzano Observatory, which he was constructing at that time.……

Engineering

In 1653, Cassini, wishing to employ the use of a meridian line, sketched a plan for a new and larger meridian line but one that would be difficult to build. His calculations were precise; the construction succeeded perfectly; and its success gave Cassini a brilliant reputation for working with engineering and structural works.

Cassini was employed by Pope Clement IX in regard to fortifications, river management, and flooding of the Po River. "Cassini composed several memoirs on the flooding of the Po River and on the means of avoiding it;……

Works

Specimen observationum Bononiensium (in Latin). Bologna: eredi Evangelista Dozza (1.). 1656.

Martis circa axem proprium revolubilis observationes Bononiae habitae (in Latin). Bologna: eredi Evangelista Dozza (1.). 1666.

Spina celeste meteora osservata in Bologna il mese di marzo 1668 (in Italian). Bologna: Emilio Maria Manolessi & fratelli. 1668.

Observations astronomiques faites en divers endroits du royaume, pendant l'année 1672 (in French).

Abregé des observations et des reflections sur la comete qui a paru au mois de Decembre 1680, et aux mois de Ianvier, Fevrier et Mars de cette annee 1681 (in French). Paris: Estienne Michallet. 1681.