Using Halley & Whiston to Predict the Comet of 1736

COMETS. Ghisilieri, Antonio (1685-1734)

Predizione della cometa dell’ anno 1736. Con riflessioni varie sopra le comete passate, e future ove si tratta il loro sistema, e calcolo.

Bologna: nella Stamperìa di Lelio dalla Volpe, 1735


Quarto: 22 x 16 cm. (6), 246 pp., (2). Collation: π1 (engraved t.p.), a2, A-Z4, Aa-Hh4. With 10 folded engraved plates.


A fine, untrimmed copy, clean and fresh, in contemporary carta rustica. Complete with all 10 plates and the engraved title (small light stain at foot). Extremely rare. Outside of Italy, copies are located at ETH Bibliothek (Zürich), Paris Observatory, and Columbia Univ. The sheets were re-issued in 1737 with another tract under the title “Il pronostico avverato fatto da monsignore Antonio Ghisilieri…” Copies of that issue are held at OSU and Brown.

The Marchese Antonio Ghisilieri (1685 - 1734) was a humanist lawyer at Bologna University and an avid amateur astronomer. In this work, published a year after his death, Ghisilieri calculates the orbital period and motion of the comet of 1735. Ghisilieri includes these predictions in the context of a much longer history of comets, describing their composition, and how to calculate their paths, declination, longitude, etc. using trigonometry and the tables of Edmund Halley and the William Whiston, Newton’s successor as Lucasian Professor at Cambridge. Pages 103 to 156 are Halley’s logarithmic tables.

The book is divided into 13 sections: I. The composition of comets (and a confirmation that they are supralunary bodies); II. The comet’s tail. III. The motion of comets. IV. The systems of Cassini, Bonaventure Cavalieri, Bernoulli, Hevelius, and Halley (with the ephemerides of Tycho and Kepler for the comets of 1577 and 1606); V. Methods of observation (and an instrument used for observation); VI. Calculating longitude, latitude, distance, etc.; VII. Calculating declination and right ascension; VIII. and IX. Parallax; X. Calculating the period; XI. Why comets are not always visible; XII. A catalogue of comets from 2312 B.C. to the present; XIII. Hevelius’ observations of the comet of 1664; Montanari’s observations of the comet of 1682 ; XIII. Periodic tables for predicting the appearance of future comets.

Antonio Ghisilieri provides calculations useful for determining future transits, based on rules contained in the tables of the English astronomer Edmund Halley. It should not be forgotten that Antonio was (and defined himself as) an amateur in the astronomy field, albeit of high profile, dedicated to the study of logarithmic calculus. In his dedicatory letter, the author’s son Filippo tells us that he found the manuscript among his father's papers and, since his father had intended to have his work printed, Filippo felt it necessary to bring the project to completion. The manuscript is kept in the Library of the Archginnasio of Bologna.

Riccardi, Bib. matematica, Vol. 1, col. 597-598; Lankford (ed.) History of Astronomy 507; not in Brüning. Kometen-Literatur. Paci, Piero. Antonio Maria Ghisilieri erudito umanista; in: Al sas, storia natura cultura. Rivista semestrale 19 (2009), pp. 48-57. Not in Brüning; OCLC: Zürich, Paris Observatory; OCLC: Columbia (our version); Brown, Ohio State (with the title: Pronostico avverato fatto da monsignore Antonio Ghisilieri vescovo d’Azoto)