Background
Giuseppe Piazzi was born on July 16, 1746 in Ponte, Italy.
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This is a reproduction of a book published before 1923. This book may have occasional imperfections such as missing or blurred pages, poor pictures, errant marks, etc. that were either part of the original artifact, or were introduced by the scanning process. We believe this work is culturally important, and despite the imperfections, have elected to bring it back into print as part of our continuing commitment to the preservation of printed works worldwide. We appreciate your understanding of the imperfections in the preservation process, and hope you enjoy this valuable book. ++++ The below data was compiled from various identification fields in the bibliographic record of this title. This data is provided as an additional tool in helping to ensure edition identification: ++++ Discorso Di Astronomia Giuseppe Piazzi
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("Della scoperta del nuovo pianeta Cerere Ferdinandea" fro...)
"Della scoperta del nuovo pianeta Cerere Ferdinandea" from Giuseppe Piazzi. Presbitero e astronomo italiano (1746-1826).
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Astronomer mathematician priest
Giuseppe Piazzi was born on July 16, 1746 in Ponte, Italy.
From 1769 until 1779 Piazzi taught mathematics in a number of Italian cities; in 1780 he was summoned by the prince of Caramanico, Bourbon viceroy of Sicily, to fill the chair of higher mathematics at the Academy of Palermo.
Palermo was then the southernmost European observatory, and the favorable climatic conditions that it provided allowed him to study more stars than had been previously cataloged, with a greater degree of accuracy.
In the course of his regular observations Piazzi, on the night of 1 January 1801, was searching a region in Taurus in which he hoped to see a star of the seventh magnitude, listed in Lacaille’s catalog, which he had previously observed.
As a young man, Piazzi entered the Theatine Order in Milan.
The viceroy encouraged Piazzi in his wish to establish an astronomical observatory in Palermo, and toward the end of the 1780’s Piazzi went to England in order to obtain the best possible equipment. In England, Piazzi met Maskelyne, William Herschel, and Ramsden.
He investigated Herschel’s large telescopes (indeed, he fell and broke his arm while examining one of them that was mounted outdoors) and, with Maskelyne, observed at Greenwich the solar eclipse of 3 June 1788.
The most important result of Piazzi’s English visit, however, was the great five-foot vertical circle, a masterpiece of eighteenth-century technology, that he commissioned from Ramsden.
It was installed in the new observatory in the Santa Ninfa tower of the royal palace of Palermo in 1789, and is still preserved there.
Before that star appeared, however, he noticed the passage of a somewhat fainter body that Lacaille had not listed.
Piazzi continued to observe the new body on the following evenings and ascertained from its movement that it must be a planet or comet.
He watched it regularly until 11 February 1801, during which period its retrograde motion ceased and it began to advance, until it had moved near enough to the sun that it could not be seen at its passage to the meridian.
As early as 24 January 1801, he wrote to Oriani:
In his reply to Piazzi, Oriani wrote, “I congratulate you on your splendid discovery of this new star.
Piazzi had made observations for a period of forty-one days, over a geocentric arc of only 30 He published his observations in 1801 as Risultati delle osservazioni della nuova stella scoperta il 10 gennaio 1801 nell’ Osservatorio di Palermo Other astronomers were eager to rediscover the new body; if it were a planet, it should be possible, on the example of Uranus, to compute from Piazzi’s observations a circular orbit, even if the arc of the presumably elliptical orbit were to prove short.
In December 1801 Gauss calculated both such an orbit and an ephemeris for the new body.
He communicated his calculations to F. X von Zach, director of the Gotha observatory, who employed them to rediscover the body in almost exactly the position that Gauss had predicted.
He proposed that Ceres and Pallas be called“asteroids, ” since they are intermingled with, and similar to, the small fixed stars.
He further suggested that these bodies were not worthy of the name of planets, since they did not occupy the space between Mars and Jupiter“with sufficient dignity. ”
(In the course of time, the question has been resolved in Piazzi’s favor, since“asteroid” has fallen into disuse, while the term“small planet” has become standard. )
In 1792 Piazzi returned to making precise determinations of the coordinates of the fixed stars.
After ten years of intense and fatiguing work, he published at Palermo, in 1803, a catalog of the medial positions of 6, 748 stars, under the title Praecipuarum stellarum inerrantium positiones mediae ineunte saeculo decimonono ex observationibus habitis in specula panoromitana ab anno 1792 ad annum 1802.
This catalog was more accurate than any of its predecessors; Zach pronounced it epochal, and the Institut de France awarded it the Lalande prize for the best astronomical work published in 1803Piazzi then carried his work a step further.
Doubting the value of the precession of the equinoxes used at that time, Piazzi undertook to determine the right ascension of a number of basic stars, relating them directly to the sun, in order to improve on earlier observations (including those made at Greenwich).
Since he was at that time in poor health, he enlisted the aid of Niccolo Cacciatore as his collaborator.
Piazzi’s Praecipuarum stellarum inerrantium positiones mediae ineunte saeculo decimonono ex observationibus habits in specula panormitana ab anno 1792 ad annum 1813 published in Palermo in 1813, cataloged the mean position of 7, 646 stars.
It was widely esteemed among astronomers, and the Institut de France again awarded Piazzi a prizeIn 1817 Piazzi published (again at Palermo) the two-volume Lezioni elementari di astronomia, which he sent to Oriani, who discussed it appreciatively.
Oriani was also anxious to persuade Piazzi to republish his earlier observations, but he did not do so.
In March 1817 Piazzi was summoned to Naples by King Ferdinand I, who wished him to supervise the completion of the observatory already under construction on the hill at Capodimonte.
The building had been begun under the direction of Joachim Murat, but had remained unfinished because of the kingdom.
Although he received an enthusiastic reception, Piazzi was reluctant to leave Palermo.
He stated his feelings in a letter to Oriani:“I shall never yield to the invitations and kindnesses that are showered upon me so that I might remain in Naples.
I would thus stain the last years of my life with the vilest ingratitude. ”
He took considerable pains in the building and equipping of the Naples observatory, and, on Oriani’s recommendation, secured Carlo Brioschi, of the Istituto Geografico Militare Lombardo, as its director.
("Della scoperta del nuovo pianeta Cerere Ferdinandea" fro...)
(This is a reproduction of a book published before 1923. T...)
