Emanuelli, Pio

(b. Rome, Italy, 3 November 1888; d. Rome, 2 July 1946)

astronomy.

The son of a clerk at the Vatican, Emanuelli became interested in astronomy when only ten years old. His first astronomical work was the observation of the solar eclipse of 20 May 1900, on which he made a report to the French astronomer Camille Flammarion. Emanuelli studied in Rome, where he served as a volunteer at the Collegio Romano Observatory until, at the age of twenty-two, he became astronomer at the Vatican Observatory.

At that time the great international astronomical enterprise was the Astrographic Catalogue, to which the Vatican Observatory contributed, and Emanuelli worked actively in that area. Even during World War I, when he was called into the army, he maintained his scientific contacts and offered advice and suggestions for the continuation of this important work.

Emanuelli computed several orbits of small planets, elements of many solar eclipses, and was particularly interested in the problem of the relativistic deflections of the stars in the neighborhood of the eclipsed sun. For some eclipses, he published celestial maps and tables with data concerning the amount of the expected displacements. Well known to all astronomers are Emanuelli’s tables for the conversion of the equatorial in galactic coordinates, which were used until the new position of the galactic poles was established.

Emanuelli had, besides his professional work in astronomy, a deep interest in the history of science and its dissemination. In these two fields he published many writings in different journals. At his death he left a large number of unpublished manuscripts, which are now deposited at the Domus Galileiana in Pisa.

BIBLIOGRAPHY

Emanuelli’s writings include “Eclisse Solare del 17 aprile 1912,” in Memorie della Società degli spettroscopisti italiani, 40 (1912), 123; observations and computations of the elements of planetary orbits, often untitled, in Astronomische Nachrichten, 178 (1908), 319; 181 (1919), 209; 215 (1922), 211; 216 (1922), 137.419; 219 (1923), 161,219; 223 (1925), 119; 234 (1929), 357; and 237 (1930), 237; “Gli eclissi di Sole totali non centrali,” in Atti dell’Accademia nazionale dei Lincei. Rendiconti della classe di scienze fisiche, matematiche e naturali, 6th ser., 8 (1928), 214; and “II polo galattico e la regione circumpolare galattica,” ibid., 9 (1929), 1096.

See also “Posizione di Venere nel 25 marzo del 1300, determinazione dell’ora in cui sono sorti Venere ed il Sole il 25 marzo del 1300 nella montagna del Purgatorio,” in Memorie della R. Accademia d’ltalia, 14 (1943), 193. A list of Emanuelli’s MSS is P. Maffei, “Gli scritti inediti di Pio Emanuelli,” in Memorie della Società astronomica italiana, 37 (1966), 803.

G. Righini