Barnaba Oriani
FRS FRSE
Fellowship of the Royal Society of Edinburgh (FRSE) is an award granted to individuals that the Royal Society of Edinburgh, Scotland's national academy of science and letters, judged to be "eminently distinguished in their subject". This soci ...
(17 July 1752 – 12 November 1832) was an Italian
priest,
geodesist,
astronomer and
scientist.
Life
Oriani was born in Garegnano (now part of
Milan), the son of a mason, and died in Milan.
After getting his elementary education in Garegnano, he went on to study at the College of San Alessandro in Milan, under the tutelage and with the support of the
Order of Barnabites,
[Students for the Exploration and Development of Space](_blank)
/ref> which he later joined. After completing his studies in the humanities, physical
Physical may refer to:
*Physical examination
In a physical examination, medical examination, or clinical examination, a medical practitioner examines a patient for any possible medical signs or symptoms of a medical condition. It generally co ...
and mathematical sciences, philosophy
Philosophy (from , ) is the systematized study of general and fundamental questions, such as those about existence, reason, knowledge, values, mind, and language. Such questions are often posed as problems to be studied or resolved. Some ...
, and theology, he was ordained a priest in 1775.Napoleon I
Napoleon Bonaparte ; it, Napoleone Bonaparte, ; co, Napulione Buonaparte. (born Napoleone Buonaparte; 15 August 1769 – 5 May 1821), later known by his regnal name Napoleon I, was a French military commander and political leader who ...
established the Republic of Lombardy
(man), (woman) lmo, lumbard, links=no (man), (woman)
, population_note =
, population_blank1_title =
, population_blank1 =
, demographics_type1 =
, demographics1_footnotes =
, demographics1_title1 =
, ...
, Oriani refused to swear an oath against the monarchy, and the new republican government modified the oath of allegiance on his behalf. He was retained in his position at the observatory and was made president of the commission appointed to regulate the new system of weights and measures.senator
A senate is a deliberative assembly, often the upper house or chamber of a bicameral legislature. The name comes from the ancient Roman Senate (Latin: ''Senatus''), so-called as an assembly of the senior (Latin: ''senex'' meaning "the el ...
, and was appointed to measure the arc of the meridian
In geodesy and navigation, a meridian arc is the curve between two points on the Earth's surface having the same longitude. The term may refer either to a segment of the meridian, or to its length.
The purpose of measuring meridian arcs is to ...
between the zeniths of Rimini and Rome.Ceres
Ceres most commonly refers to:
* Ceres (dwarf planet), the largest asteroid
* Ceres (mythology), the Roman goddess of agriculture
Ceres may also refer to:
Places
Brazil
* Ceres, Goiás, Brazil
* Ceres Microregion, in north-central Goiás st ...
. Oriani and Piazzi worked together for thirty-seven years, cooperating on many astronomical observations.
Astronomy
Given his strong interest in astronomy, Oriani was appointed on the staff of the Observatory of Brera in Milan in 1776, becoming assistant astronomer in 1778 and director in 1802. In 1778 he began publishing various in-depth dissertations on astronomical objects, the ''Effemeridi di Milano'' ( Ephemerides of Milan).[Alexandro Malaspina Research Centre](_blank)
After others had shown that Uranus was not on a parabolic orbit but rather in a roughly circular orbit, he calculated the orbit in 1783. In 1789, Oriani improved his calculations by accounting for the gravitational effects of Jupiter and Saturn
Saturn is the sixth planet from the Sun and the second-largest in the Solar System, after Jupiter. It is a gas giant with an average radius of about nine and a half times that of Earth. It has only one-eighth the average density of Earth; h ...
.asteroid
An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere.
...
4540 "Oriani". This asteroid had been discovered at the Osservatorio San Vittore
The San Vittore Observatory ( it, Osservatorio San Vittore, obs. code: 552) is an astronomical observatory in Bologna, Italy. In the years from 1975 to 1981 the San Vittore Observatory (Bologna) Italy participated to the International Pl ...
in Bologna, Italy on 6 November 1988.
Oriani's theorem
In ''De refractionibus astronomicis'', Oriani showed that astronomical refraction could be expanded as a series of odd powers of (tan Z), where Z is the observed zenith distance. Such a series had previously been derived by J. H. Lambert, who dropped all but the first term. However, Oriani investigated the higher terms, and he found that neither of the first two terms depended on the structure of the atmosphere.
The series expansion he obtained was effective at up to 85 degrees from the zenith. Unlike previous approximations, however, Oriani's two-term expression did not depend on a hypothesis regarding atmospheric temperature or air density
The density of air or atmospheric density, denoted '' ρ'', is the mass per unit volume of Earth's atmosphere. Air density, like air pressure, decreases with increasing altitude. It also changes with variation in atmospheric pressure, temperature a ...
in relation to altitude. Thus, the effects of atmospheric curvature are only dependent upon the temperature and pressure ''at the location of the observer''.
Oriani's theorem explains why Cassini's uniform-density model works well except near the horizon—the atmospheric refraction from the zenith to a zenith distance of 70° is not dependent on the details of the distribution of the gas.
See also
* List of Roman Catholic scientist-clerics
References
{{DEFAULTSORT:Oriani, Barnaba
1752 births
1832 deaths
Clergy from Milan
18th-century Italian astronomers
19th-century Italian astronomers
Catholic clergy scientists
Fellows of the Royal Society
Scientists from Milan