Astronomer, b. at Caprese in Tuscany, 30 Jan., 1787; d. at Padua, 26 June, 1877. He received his first instruction from his parental uncle, the Abate Giovanni Battista Santini. This excellent teacher implanted at the same time the deep religious sentiments which Santini preserved throughout his life. After finishing his philosophical studies in the school year 1801-2, at the seminary of Prato, he entered in 1802 the University of Pisa. He very soon abandoned the study of law in order to devote himself, under the direction of Prof. Paoli and Abate Pacchiano, exclusively to mathematics and the natural sciences. It appears that at Pisa Santini still wore the cassock. This circumstance, and possibly also his being confused with his uncle Giovanni Battista, may account for the fact that in bibliographical dictionaries he still figures under the title of abate. It is certain, however, that he never received major orders. In 1810 he married Teresa Pastrovich, and one year after her death, in 1843, he contracted a second marriage with Adriana Conforti, who outlived him. During his stay at Pisa he won by his diligence the love and confidence not only of his professors but also of the rector of the university and of the influential Fossombroni. At their urgent suggestion Santini's family, especially his uncle, made great sacrifices to enable him to continue his studies in Milan (1805-1806) under Oriani, Cesaris, and Carlini. On 17 Oct., 1806, the Italian Government appointed him assistant to the director of the observatory at Padua, Abate Chiminello, whom he succeeded in 1814. In 1813 the university offered him the chair of astronomy, a position in which he was confirmed by the Emperor Francis I in 1818 after the Venetian territory had become part of Austria. In addition he taught for several years, as substitute, elementary algebra, geometry, and higher mathematics. During the school years 1824-1825 and 1856-7 he was rector of the university, and from 1845 to 1872 director of mathematical studies. Towards the end of 1873 he suffered repeatedly from fainting spells which were followed by a steadily increasing physical and mental weakness and final breakdown. He died in his ninety-first year at his villa, Noventa Padovana.

Both as a practical and theoretic astronomer, Santini has made the Observatory of Padua famous. When he took charge the observatory was located in an old fortified tower, in a precarious condition. The most valuable instrument he found was a Ramsden mural quadrant eight feet in diameter. On account of the political complications and Chiminello's protracted illness, the practical work was reduced to a minimum-regular meteorological observations. Santini at once began to take careful observations of comets, planets, planetoids, occultations, and eclipses. In 1811 he determined the latitude of Padua with the aid of Gauss's method of three stars in the same altitude, and in 1815 again, with a new repeating circle. In 1822, '24, and '28 he assisted the astronomical and geodetic service of Italy by making observations in longitude. Constantly striving to equip this institute in accordance with the latest requirements of science, he installed in 1823 a new Utzschneider equatorial, and in 1837 a new meridian circle. With these last he began at once to make zonal observations for a catalogue of stars between declination +10° and -10°, an undertaking which he carried out on a large scale, and which he, with the aid of his assistant, Trettenero, completed in 1857, after ten years of work. In 1843 he made a scientific journey through Germany, and in the most scientific centres he conferred with distinguished savants in his own and related fields. As a theoretic astronomer, Santini deserves notice for his researches concerning the comets. In the Encke-Galle catalogue he is credited with the calculation of nineteen orbits. He acquired his greatest fame by his calculations of the orbital disturbances during the period from 1832-1852 caused by the- great planets on the comet of Biela. The time and place of the appearance of this comet in 1846 corresponded exactly with previous calculations. In 1819-20 he published his "Elementi di Astronomia" (2nd ed., Padua, 1830), a work in two parts, of classic soberness and thoroughness. In 1828 appeared his "Teorica degli Stromenti Ottici", also published in Padua, in which he explains by means of the most simple formulas the construction of the different kinds of telescopes, microscopes etc. A number of dissertations on geodetic and astronomic subjects from his pen appeared in the annals of learned associations, in the "Correspondence du Baron de Zach", "Astronomische Nachrichten", etc. Besides some twenty Italian scientific societies, Santini became a member in 1825 of the London Royal Astronomical Society; in 1845 a corresponding member of the Institut de France; and in 1847 member of the Kaiserliche Akademie der Wissenschaften of Vienna. When in 1866 Venice was separated from Austria, he became a corresponding member of the last-named association. Danish, Austrian, Spanish, and Italian decorations were bestowed upon him. A complete list of his writings may be found in the "Discorso" (pp. 42-67) by Lorenzoni, mentioned below.

LORENZONI, Giovanni Santini, la sua vita e le sue opere. Discorso letto nella chiesa di S. Sofia in Padova (Padua, 1877; IDEM, In occasione del primo centenario dalla nascita dell' astronomo Santini (Padua, 1887); VON WURZBACH, Biograf. Lexikon des Kaiserthums Ostreich mit Unterstutzung durch die Kais. Akad. der Wiss. (Vienna, 1874), s. v,; POGGENDORFF, Biograf. litt. Handb., II (Leipzig, 1859), s. v.

J. Stein.