Giuseppe Piazzi
Encyclopedia
Giuseppe Piazzi was an Italian
Catholic priest of the Theatine order
, mathematician
, and astronomer
. He was born in Ponte in Valtellina
, and died in Naples
. He established an observatory at Palermo
, now the Osservatorio Astronomico di Palermo – Giuseppe S. Vaiana.
, quite likely attending Giovan Battista Beccaria's lessons. In the years 1768-1770 he was resident at the Theatines' Home in S. Andrea della Valle, Rome
, while studying Mathematics under Jd
.
In July 1770 he took the chair of Mathematics at the University of Malta
. In December 1773 he moved to Ravenna
as "prefetto degli studenti" and lecturer in Philosophy and Mathematics at the Collegio dei Nobili, where he stayed until the beginning of 1779. After a short period spent in Cremona
and in Rome, in March 1781 Piazzi moved to Palermo
as lecturer in Mathematics at the University of Palermo
(at the time known as "Accademia de' Regj Studi").
He kept this position until 19 January 1787, when he became Professor of Astronomy. Almost at the same time he was granted permission to spend two years in Paris and London in order to undergo some practical training in astronomy and also to get some instruments to be specially built for the Palermo Observatory, whose foundation he was in charge of.
In the period spent abroad, from 13 March 1787 until the end of 1789, Piazzi became acquainted with the major French and English astronomers of his time and was able to have the famous altazimuthal circle made by Jesse Ramsden
, one of the most skilled instrument-makers of the 18th century. The circle was the most important instrument of the Palermo Observatory, whose official foundation took place on 1 July 1790.
In 1817 King Ferdinand
put Piazzi in charge of the completion of the Capodimonte (Naples) Observatory, naming him General Director of the Naples and Sicily Observatories.
" from Herschel
, and the original Rotanev and Sualocin. The work on this catalogue was started in 1789, enabling Piazzi and collaborators to observe the sky methodically. The catalogue wasn't finished for first edition publication until 1803.
Spurred by the success discovering Ceres (see below), and in the line of his catalogue program, Piazzi studied the proper motions of stars in order to find parallax measurement candidates. One of them, 61 Cygni
, was specially appointed as a good candidate for measuring a parallax, which was later performed by Friedrich Wilhelm Bessel. The star system 61 Cygni
is sometimes still called variously Piazzi's Flying Star and Bessel's Star.
, today known as the largest member of the asteroid belt
. On January 1, 1801, Piazzi discovered a "stellar object" that moved against the background of star
s. At first he thought it was a fixed star, but once he noticed that it moved, he became convinced it was a planet, or as he called it, "a new star".
In his journal, he wrote: "The light was a little faint, and of the colour of Jupiter
, but similar to many others which generally are reckoned of the eighth magnitude
. Therefore I had no doubt of its being any other than a fixed star. In the evening of the second I repeated my observations, and having found that it did not correspond either in time or in distance from the zenith with the former observation, I began to entertain some doubts of its accuracy. I conceived afterwards a great suspicion that it might be a new star. The evening of the third, my suspicion was converted into certainty, being assured it was not a fixed star. Nevertheless before I made it known, I waited till the evening of the fourth, when I had the satisfaction to see it had moved at the same rate as on the preceding days."
In spite of his assumption that it was a planet, he took the conservative route and announced it as a comet
. In a letter to astronomer Barnaba Oriani
of Milan
he made his suspicions known in writing:
He was not able to observe it long enough as it was soon lost in the glare of the Sun
. Unable to compute its orbit
with existing methods, the renowned mathematician Carl Friedrich Gauss
developed a new method of orbit calculation that allowed astronomers to locate it again. After its orbit was better determined, it was clear that Piazzi's assumption was correct and this object was not a comet but more like a small planet
. Coincidentally, it was also almost exactly where the Titius-Bode law
predicted a planet would be.
Piazzi named it "Ceres Ferdinandea," after the Roman
and Sicilian goddess of grain and King Ferdinand IV
of Naples
and Sicily
. The Ferdinandea part was later dropped for political reasons. Ceres turned out to be the first, and largest, of the asteroid
s existing within the asteroid belt
. Ceres is today called a dwarf planet
.
was dedicated in the main plaza of his birthplace, Ponte.
In 1923, the 1000th asteroid to be numbered was named 1000 Piazzia
in his honor. The lunar crater Piazzi
was named after him in 1935. More recently, a large albedo
feature, probably a crater
, imaged by the Hubble Space Telescope
on Ceres, has been informally named Piazzi.
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
Catholic priest of the Theatine order
Theatines
The Theatines or the Congregation of Clerks Regular of the Divine Providence are a male religious order of the Catholic Church, with the post-nominal initials "C.R."-Foundation:...
, mathematician
Mathematician
A mathematician is a person whose primary area of study is the field of mathematics. Mathematicians are concerned with quantity, structure, space, and change....
, and astronomer
Astronomer
An astronomer is a scientist who studies celestial bodies such as planets, stars and galaxies.Historically, astronomy was more concerned with the classification and description of phenomena in the sky, while astrophysics attempted to explain these phenomena and the differences between them using...
. He was born in Ponte in Valtellina
Ponte in Valtellina
Ponte in Valtellina is a comune in the Province of Sondrio in the Italian region Lombardy, located about 100 km northeast of Milan and about 9 km east of Sondrio...
, and died in Naples
Naples
Naples is a city in Southern Italy, situated on the country's west coast by the Gulf of Naples. Lying between two notable volcanic regions, Mount Vesuvius and the Phlegraean Fields, it is the capital of the region of Campania and of the province of Naples...
. He established an observatory at Palermo
Palermo
Palermo is a city in Southern Italy, the capital of both the autonomous region of Sicily and the Province of Palermo. The city is noted for its history, culture, architecture and gastronomy, playing an important role throughout much of its existence; it is over 2,700 years old...
, now the Osservatorio Astronomico di Palermo – Giuseppe S. Vaiana.
Biography
No documented account of Piazzi's scientific education is available in any of the biographies of the astronomer, even in the oldest ones. Piazzi certainly did some studies in TurinTurin
Turin is a city and major business and cultural centre in northern Italy, capital of the Piedmont region, located mainly on the left bank of the Po River and surrounded by the Alpine arch. The population of the city proper is 909,193 while the population of the urban area is estimated by Eurostat...
, quite likely attending Giovan Battista Beccaria's lessons. In the years 1768-1770 he was resident at the Theatines' Home in S. Andrea della Valle, Rome
Rome
Rome is the capital of Italy and the country's largest and most populated city and comune, with over 2.7 million residents in . The city is located in the central-western portion of the Italian Peninsula, on the Tiber River within the Lazio region of Italy.Rome's history spans two and a half...
, while studying Mathematics under Jd
JD
- General usage :* Juris Doctor , a law degree held by some lawyers in certain countries* Job description, an acronym for a person's nature of job or terms of reference * Jack Daniel's, a whiskey distilled in Tennessee...
.
In July 1770 he took the chair of Mathematics at the University of Malta
University of Malta
The University of Malta is the highest educational institution in Malta Europe and is one of the most respected universities in Europe. The University offers undergraduate Bachelor's Degrees, postgraduate Master's Degrees and postgraduate Doctorates .-History:The University of Malta was founded in...
. In December 1773 he moved to Ravenna
Ravenna
Ravenna is the capital city of the Province of Ravenna in the Emilia-Romagna region of Italy and the second largest comune in Italy by land area, although, at , it is little more than half the size of the largest comune, Rome...
as "prefetto degli studenti" and lecturer in Philosophy and Mathematics at the Collegio dei Nobili, where he stayed until the beginning of 1779. After a short period spent in Cremona
Cremona
Cremona is a city and comune in northern Italy, situated in Lombardy, on the left bank of the Po River in the middle of the Pianura Padana . It is the capital of the province of Cremona and the seat of the local City and Province governments...
and in Rome, in March 1781 Piazzi moved to Palermo
Palermo
Palermo is a city in Southern Italy, the capital of both the autonomous region of Sicily and the Province of Palermo. The city is noted for its history, culture, architecture and gastronomy, playing an important role throughout much of its existence; it is over 2,700 years old...
as lecturer in Mathematics at the University of Palermo
University of Palermo
The University of Palermo is a university located in Palermo, Italy, and founded in 1806. It is organized in 12 Faculties.-History:The University of Palermo was officially founded in 1806, although its earliest roots date back to 1498 when medicine and law were taught there...
(at the time known as "Accademia de' Regj Studi").
He kept this position until 19 January 1787, when he became Professor of Astronomy. Almost at the same time he was granted permission to spend two years in Paris and London in order to undergo some practical training in astronomy and also to get some instruments to be specially built for the Palermo Observatory, whose foundation he was in charge of.
In the period spent abroad, from 13 March 1787 until the end of 1789, Piazzi became acquainted with the major French and English astronomers of his time and was able to have the famous altazimuthal circle made by Jesse Ramsden
Jesse Ramsden
Jesse Ramsden FRSE was an English astronomical and scientific instrument maker.Ramsden was born at Salterhebble, Halifax, West Riding of Yorkshire, England. After serving his apprenticeship with a cloth-worker in Halifax, he went in 1755 to London, where in 1758 he was apprenticed to a...
, one of the most skilled instrument-makers of the 18th century. The circle was the most important instrument of the Palermo Observatory, whose official foundation took place on 1 July 1790.
In 1817 King Ferdinand
Ferdinand I of the Two Sicilies
Ferdinand I reigned variously over Naples, Sicily, and the Two Sicilies from 1759 until his death. He was the third son of King Charles III of Spain by his wife Maria Amalia of Saxony. On 10 August 1759, Charles succeeded his elder brother, Ferdinand VI, as King Charles III of Spain...
put Piazzi in charge of the completion of the Capodimonte (Naples) Observatory, naming him General Director of the Naples and Sicily Observatories.
Star cataloguing
He supervised the compilation of the Palermo Catalogue of stars, containing 7,646 star entries with unprecedented precision, including the star names "Garnet StarMu Cephei
Mu Cephei , also known as Herschel's Garnet Star, is a red supergiant star in the constellation Cepheus. It is one of the largest and most luminous stars known in the Milky Way...
" from Herschel
William Herschel
Sir Frederick William Herschel, KH, FRS, German: Friedrich Wilhelm Herschel was a German-born British astronomer, technical expert, and composer. Born in Hanover, Wilhelm first followed his father into the Military Band of Hanover, but emigrated to Britain at age 19...
, and the original Rotanev and Sualocin. The work on this catalogue was started in 1789, enabling Piazzi and collaborators to observe the sky methodically. The catalogue wasn't finished for first edition publication until 1803.
Spurred by the success discovering Ceres (see below), and in the line of his catalogue program, Piazzi studied the proper motions of stars in order to find parallax measurement candidates. One of them, 61 Cygni
61 Cygni
61 Cygni,Not to be confused with 16 Cygni, a more distant system containing two G-type stars harboring the gas giant planet 16 Cygni Bb. sometimes called Bessel's Star or Piazzi's Flying Star, is a binary star system in the constellation Cygnus...
, was specially appointed as a good candidate for measuring a parallax, which was later performed by Friedrich Wilhelm Bessel. The star system 61 Cygni
61 Cygni
61 Cygni,Not to be confused with 16 Cygni, a more distant system containing two G-type stars harboring the gas giant planet 16 Cygni Bb. sometimes called Bessel's Star or Piazzi's Flying Star, is a binary star system in the constellation Cygnus...
is sometimes still called variously Piazzi's Flying Star and Bessel's Star.
The asteroid Ceres
Piazzi discovered Ceres1 Ceres
Ceres, formally 1 Ceres, is the smallest identified dwarf planet in the Solar System and the only one in the asteroid belt. With a diameter of about 950 km, Ceres is by far the largest and most-massive asteroid, comprising about a third of the mass of the asteroid belt. Discovered on 1 January 1801...
, today known as the largest member of the asteroid belt
Asteroid belt
The asteroid belt is the region of the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets...
. On January 1, 1801, Piazzi discovered a "stellar object" that moved against the background of star
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
s. At first he thought it was a fixed star, but once he noticed that it moved, he became convinced it was a planet, or as he called it, "a new star".
In his journal, he wrote: "The light was a little faint, and of the colour of Jupiter
Jupiter
Jupiter is the fifth planet from the Sun and the largest planet within the Solar System. It is a gas giant with mass one-thousandth that of the Sun but is two and a half times the mass of all the other planets in our Solar System combined. Jupiter is classified as a gas giant along with Saturn,...
, but similar to many others which generally are reckoned of the eighth magnitude
Apparent magnitude
The apparent magnitude of a celestial body is a measure of its brightness as seen by an observer on Earth, adjusted to the value it would have in the absence of the atmosphere...
. Therefore I had no doubt of its being any other than a fixed star. In the evening of the second I repeated my observations, and having found that it did not correspond either in time or in distance from the zenith with the former observation, I began to entertain some doubts of its accuracy. I conceived afterwards a great suspicion that it might be a new star. The evening of the third, my suspicion was converted into certainty, being assured it was not a fixed star. Nevertheless before I made it known, I waited till the evening of the fourth, when I had the satisfaction to see it had moved at the same rate as on the preceding days."
In spite of his assumption that it was a planet, he took the conservative route and announced it as a comet
Comet
A comet is an icy small Solar System body that, when close enough to the Sun, displays a visible coma and sometimes also a tail. These phenomena are both due to the effects of solar radiation and the solar wind upon the nucleus of the comet...
. In a letter to astronomer Barnaba Oriani
Barnaba Oriani
__FORCETOC__Barnaba Oriani was an Italian priest, geodesist, astronomer and scientist.-Life:Oriani was born in Garegnano , the son of a mason, and died in Milan....
of Milan
Milan
Milan is the second-largest city in Italy and the capital city of the region of Lombardy and of the province of Milan. The city proper has a population of about 1.3 million, while its urban area, roughly coinciding with its administrative province and the bordering Province of Monza and Brianza ,...
he made his suspicions known in writing:
- "I have announced this star as a comet, but since it is not accompanied by any nebulosity and, further, since its movement is so slow and rather uniform, it has occurred to me several times that it might be something better than a comet. But I have been careful not to advance this supposition to the public."
He was not able to observe it long enough as it was soon lost in the glare of the Sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
. Unable to compute its orbit
Orbit
In physics, an orbit is the gravitationally curved path of an object around a point in space, for example the orbit of a planet around the center of a star system, such as the Solar System...
with existing methods, the renowned mathematician Carl Friedrich Gauss
Carl Friedrich Gauss
Johann Carl Friedrich Gauss was a German mathematician and scientist who contributed significantly to many fields, including number theory, statistics, analysis, differential geometry, geodesy, geophysics, electrostatics, astronomy and optics.Sometimes referred to as the Princeps mathematicorum...
developed a new method of orbit calculation that allowed astronomers to locate it again. After its orbit was better determined, it was clear that Piazzi's assumption was correct and this object was not a comet but more like a small planet
Planet
A planet is a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals.The term planet is ancient, with ties to history, science,...
. Coincidentally, it was also almost exactly where the Titius-Bode law
Titius-Bode law
The Titius–Bode law is a hypothesis that the bodies in some orbital systems, including the Sun's, orbit at semi-major axes in a function of planetary sequence...
predicted a planet would be.
Piazzi named it "Ceres Ferdinandea," after the Roman
Roman mythology
Roman mythology is the body of traditional stories pertaining to ancient Rome's legendary origins and religious system, as represented in the literature and visual arts of the Romans...
and Sicilian goddess of grain and King Ferdinand IV
Ferdinand I of the Two Sicilies
Ferdinand I reigned variously over Naples, Sicily, and the Two Sicilies from 1759 until his death. He was the third son of King Charles III of Spain by his wife Maria Amalia of Saxony. On 10 August 1759, Charles succeeded his elder brother, Ferdinand VI, as King Charles III of Spain...
of Naples
Naples
Naples is a city in Southern Italy, situated on the country's west coast by the Gulf of Naples. Lying between two notable volcanic regions, Mount Vesuvius and the Phlegraean Fields, it is the capital of the region of Campania and of the province of Naples...
and Sicily
Sicily
Sicily is a region of Italy, and is the largest island in the Mediterranean Sea. Along with the surrounding minor islands, it constitutes an autonomous region of Italy, the Regione Autonoma Siciliana Sicily has a rich and unique culture, especially with regard to the arts, music, literature,...
. The Ferdinandea part was later dropped for political reasons. Ceres turned out to be the first, and largest, of the asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
s existing within the asteroid belt
Asteroid belt
The asteroid belt is the region of the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets...
. Ceres is today called a dwarf planet
Dwarf planet
A dwarf planet, as defined by the International Astronomical Union , is a celestial body orbiting the Sun that is massive enough to be spherical as a result of its own gravity but has not cleared its neighboring region of planetesimals and is not a satellite...
.
Posthumous honors
In 1871, a memorial statue of Piazzi sculpted by Costantino CortiCostantino Corti
Costantino Corti was a Milanese sculptor who exhibited at Brera and in Florence, London, and Paris. Corti was most noted for his colossal statue Lucifer...
was dedicated in the main plaza of his birthplace, Ponte.
In 1923, the 1000th asteroid to be numbered was named 1000 Piazzia
1000 Piazzia
1000 Piazzia, discovered in 1923, is a main-belt asteroid orbiting the Sun. It was the 1000th minor planet to be numbered, and was named in honour of Giuseppe Piazzi, who discovered the first asteroid, 1 Ceres....
in his honor. The lunar crater Piazzi
Piazzi (crater)
Piazzi is a lunar crater that is located near the southwestern limb of the Moon, and is attached to the southeastern rim of the walled plain Lagrange. About three crater diameters to the south is the crater Inghirami...
was named after him in 1935. More recently, a large albedo
Albedo
Albedo , or reflection coefficient, is the diffuse reflectivity or reflecting power of a surface. It is defined as the ratio of reflected radiation from the surface to incident radiation upon it...
feature, probably a crater
Impact crater
In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...
, imaged by the Hubble Space Telescope
Hubble Space Telescope
The Hubble Space Telescope is a space telescope that was carried into orbit by a Space Shuttle in 1990 and remains in operation. A 2.4 meter aperture telescope in low Earth orbit, Hubble's four main instruments observe in the near ultraviolet, visible, and near infrared...
on Ceres, has been informally named Piazzi.
See also
- Niccolò CacciatoreNiccolò CacciatoreNiccolò Cacciatore was an Italian astronomer.Cacciatore was born at Casteltermini, in Sicily. While studying mathematics and physics in Palermo, he became acquainted with Giuseppe Piazzi, head of the Palermo Astronomical Observatory, and became a graduate student assistant at the observatory in...
, his assistant and successor on the post as director - List of Roman Catholic scientist-clerics