Theoriae motus cometae anni 1664 pars prima. Ea praeferens, quae ex primis observationibus ad futurorum motuum praenotionem deduci potuere, cum nova investigationis methodo, tum in eodem, tum in comete novissimo anni 1665 ad praxim revocata [...]

Autore: CASSINI, Giovanni Domenico (1625-1712)

Tipografo: Fabio Di Falco

Dati tipografici: Roma, 1665



[4], 60 [i.e. 62], [2] pp. and [1] engraved folding plate. Collation: [π]2 A-N2 O1 [P]-[Q]2 [χ]1. Leaf O1 is numbered 52½ on recto, while the verso is blank. The last leaf [χ]1 contains the index on recto and the errata corrige and the colophon on verso. With several tables and woodcut diagrams in text. Decorative woodcut initials and tailpieces.

Italian Union Catalogue, IT\ICCU\UFIE\002562; P. Riccardi, Biblioteca matematica italiana, Milano, 1952, I.1, col. 276, no. 9; J.J. Lalande, Bibliographie astronomique, Paris, 1803, p. 261.


(bound with:)

Lettera astronomica di Gio: Domenico Cassini al Sig. abbate Ottavio Falconieri. Sopra l'ombre de Pianetini Medicei in Giove. Colophon: Rome, Fabio Di Falco, 1665

7, [1 blank] pp. Collation: A-B2. Woodcut initial.

Italian Union Catalogue, IT\ICCU\UFIE\002579; Riccardi, op. cit., I.1, col. 277, no. 13; Lalande, op. cit., p. 258.


(bound with:)

Tabulae quotidianae revolutionis macularum Iovis. Nuperrimè adinventae a Ioanne Dominico Cassino [...] Rome, Fabio Di Falco, 1665

[2] leaves. Collation: [A]2. Title page and 3 pages of tables.

Italian Union Catalogue, IT\ICCU\UFIE\002585; Riccardi, op. cit., I.1, col. 277, no. 15; Lalande, op. cit., p. 258


(bound with:)

Lettere astronomiche di Gio. Domenico Cassini al Sig. Abbate Ottavio Falconieri sopra la varietà delle macchie osservate in Giove e loro diurne rivoluzioni. [Rome, Fabio di Falco, 1665].

12 pp. Collation: A-C2. Decorative woodcut initials. It contains three letters to Ottavio Falconieri (1636-1675) dated from Rome, 12, 20, and 26 October 1665. The catchword at end of p. 12, “Illu-“, may indicate that the work was originally meant to continue; all copies though have the same number of pages. Cassini's related set of tables, with title Tabulae quotidianae revolutionis macularum Iovis (see previous item), may have been issued with these Lettere.

Italian Union Catalogue, IT\ICCU\UFIE\002584; Riccardi, op. cit., I.1, col. 277, no. 12; Lalande, op. cit., p. 258.


(bound with:)

Lettere astronomiche di Gio. Domenico Cassini al Signor Abbate Ottavio Falconieri sopra il confronto di alcune osservazioni delle comete di quest'anno 1665. Colophon: Rome, Fabio di Falco, 1665.

22, [2] pp. Collation: [A]2 B-F2. Woodcut initials. It contains 2 letters to Ottavio Falconieri (1646-1676) dated from Rome, 9 and 20 Mai 1665.

Italian Union Catalogue, IT\ICCU\UFIE\002563; Riccardi, op. cit., I.1, col. 277, no. 14; Lalande, op. cit., p. 258.


Five works in one volume, folio (350x240 mm). Contemporary cardboards “alla rutica” (slightly stained, small occasional repairs to spine and joints, but overall very well preserved). On the front pastedown contemporary manuscript shelf mark note. Some light foxing and browning, a few quires more strongly browned, but an extremely genuine copy in its original binding. Uncut with deckle edges.


First edition of five rare works containing Cassini's very accurate observations of the comet of 1664 and Jupiter's spots, made possible by his new collaboration with the lensmakers Eustachio Divini and, above all, Giuseppe Campani. “How Giuseppe Campani and Cassini first became acquainted is indicated to some degree in notes that the astronomer left after his death, which later were compiled into a biographical account by his great grandson Cassini IV. By 1664, at some time after the two young men first met in person, while Cassini was visiting Rome, he wrote that he had been invited by Campani ‘to come with him to Monte Citorio to observe Jupiter with a number of persons of distinction who were to meet there to test his telescopes'. It was while making observations on that occasion that Cassini discovered the shadows of the satellites of Jupiter. Campani subsequently presented him with the gift of an excellent telescope he had made having a focal length of 17 palms (3.8 meters), which Cassini later took with him on his voyage to Tuscany and subsequently brought with him when he moved to Paris. It was with this instrument that Cassini discovered the permanent spots of Jupiter in July 1665” (S. Bedini & C. Zanetti, Giuseppe Campani, “Inventor Romae,” an Uncommon Genius, Leiden, 2021, p. 579).

Cassini observed the 1664 comet through a new Campani telescope, mentioned in the preface of the Theoriae motus cometae anni 1664, “in the presence of Queen Christina [to whom the Theoriae motus cometae anni 1664 is dedicated] and formulated a new theory (in agreement with the Tychonian system) in which the orbit of the comet is a great circle whose center is situated in the direction of Sirius and whose perigee is beyond the orbit of Saturn” (C.C. Gillespie, ed., Dictionary of Scientific Biography, New York, 1971, III, p. 101). The large folding plate that accompanies the Theoriae motus cometae anni 1664, shows the position of the comet detected in the southern hemisphere between December 18, 1664 and January 15, 1665.

“A new and fertile direction now opened up for Cassini's observations. Through his friendship with the famous Roman lensmakers Giuseppe Campani and Eustachio Divini, Cassini, beginning in 1664, was able to obtain from them powerful celestial telescopes of great focal length. He used these instruments - very delicate and extremely accurate for the time - with great skill, and made within several years a remarkable series of observations on the planetary surfaces, which led him to important discoveries. In July 1664 he detected the shadow of certain satellites on Jupiter's surfaces and was thus able to study the revolution of the satellites and to demonstrate that of the planet: the period that he attributed to the latter, 9h 56m, is close to the presently accepted value. At the same time, he described the whole group of the planet's bands, as well as its spots, and observed its flattening” (D.S.B., op. cit., III, p. 101).

For what concerns Cassini's position on the heliocentric system, he stated on several occasions “that although, when in opposition to the Sun, the comet could be used by Copernicans as proof of the mobility of the earth, such motion could also be explained within a Tychonic geometric system. [He reaffirmed that also in the Lettere astronomiche al Signor Abbate Ottavio Falconieri sopra il confronto di alcune osservazioni delle comete di quest'anno 1665 (pp. 6-7)]. Nevertheless, Cassini's consistent public position during this period was that he could not accept the concept of a moving Earth. This public stance may well have been to appease ecclesiastical authorities in the Papal States, to which Bologna belonged, especially after the renewed Papal ban of Copernicanism in 1664” (L. Boschiero, Giovanni Borelli and the Comets of 1664-1665, in: “Journal for the History of Astronomy”, vol. 40, January 2009, p. 27).


Giovanni Domenico Cassini, astronomer, mathematician, engineer, and philosopher, was the progenitor of a dynasty of astronomers who linked their name to the history of the Paris Observatory from 1669 to 1832: in fact, Giovanni Domenico was father to Jacques Cassini (1677-1756), grandfather to Cesar François Cassini de Thury (1714-1784), and great-grandfather to Jean Dominique Cassini (1748-1845).

From an early age Cassini began to study astronomy with great passion, making such rapid progress that in 1650, at the age of twenty-five, he was appointed by the Bologna Senate, through the intercession of Marquis Cornelio Malvasia, a rich amateur astronomer and senator of Bologna, to the first chair of astronomy in the University. The chair was vacant after the death in 1647 of Bonaventura Cavalieri, the first to express the Copernican theory and Galileo's discoveries in public lectures. Together with Malvasia, Cassini observed the comet that appeared in late 1652, on which he published De cometa anni 1652 et 1653 (Modena, 1653). Subsequently devoting himself more and more to the study of the planets, in order to carry out his observations with more precision, Cassini designed and built in the S. Petronio cathedral a more precise sundial than the one drawn by Ignatio Danti a century earlier; he then reported his calculations in the Novum lumen astronomicum ex novo heliometro (Bologna, 1654). Although astronomy remained his main occupation, Cassini was obliged to engage also in hydraulics and fortifications projects, and was appointed superintendent of waters and fortifications of the Papal State.

After the publication, in 1668, of the Ephemerides Bononienses mediceorum syderum, ex hypothesibus et tabulis, a work containing precise tables of the movements of Jupiter's satellites that attracted the attention of the Paris Academy of Sciences founded by Colbert in 1666, Cassini was invited to move to France with the offer of a pension from the king. He arrived in Paris in 1669, and Louis XIV himself showed him the design of the new observatory under construction, whose plans Cassini strove in vain to modify. After living for some time at the Louvre, in 1671 he moved to the apartment prepared especially for him at observatory, where he established a precise daily schedule of research and surveys. As early as 1673 he was recalled to Italy by the pope, but Colbert was able to get him the French citizenship. His son Giacomo, born in 1677, was educated at the observatory, where he was later destined to succeed his father as director. Cassini's fame as an astronomer grew after his prediction, made after a single observation, of the path of a comet appeared in December 1680, and also thanks to the previous discovery of two new satellites of Saturn, on which he published the Découverte de deux nouvelles planètes autours de Saturne (Paris, 1673).

While resisting the insistence of Christina of Sweden, who wanted him in Rome to direct an observatory she had planned to build at Villa Riario, Cassini returned to Italy in 1695 only on a short trip with his son Giacomo. In Bologna he corrected the errors that time had made to his sundial in S. Petronio. Back in Paris, he was occupied several years in the construction of another sundial, much more extensive than the one in Bologna. Cassini spent the last years of his life totally blind like Galileo, dictating his diary to a secretary every evening. He died in Paris on September 14, 1712, at the age of eighty-seven.

Cassini can be considered as the organizer of astronomical studies in France, as he gave them a method and a program of research that remained the basis for later observations. He also left some forty memoirs in the proceedings of the Académie Royale, as well as many unpublished papers. He was not a theoretician, but rather a skilled and gifted observer (cf. A. De Ferrari, Cassini, Giovanni Domenico, in: “Dizionario Biografico degli Italiani”, vol. 21, 1978, s.v.; see also D.S.B, op. cit., III, pp. 100-104).


THIS EXEPCTIONAL SAMMELBAND IN CONTEMPORARY BINDING SEEMS TO INCLUDE ALL CASSINI'S PUBLICATIONS PRINTED IN ROME BY DI FALCO IN 1665 BUT ONE: the four-page pamphlet Ephemeris prima motus cometae novissimi mense aprili 1665, in qua supponitur maximi cometae circuli declinatio ab ecliptica ad Boream gr. 25. 30. (see Riccardi, op. cit., I.1, coll. 276-277, no. 11).