Английская Википедия:Celestial police
The celestial police (Шаблон:Lang-de), officially the United Astronomical Society (Шаблон:Lang-de), was an international cooperation of numerous European observatories to search for objects expected between the orbits of Mars and Jupiter. It was formed in 1800 at the second European congress of astronomers. At the first such congress, in 1798, the French mathematician Jérôme Lalande had called for a coordinated search, in which each participating observatory would patrol a particular part of the sky. [1]
Inspired by the work of William Herschel and the discovery of Uranus, the first planet not known to the ancients, the celestial police made discoveries of numerous objects in orbit around the Sun, notably several of those in orbit between Mars and Jupiter, which would lead to the identification of the asteroid belt.
History
The group was founded in 1800 by Franz Xaver von Zach, a German astronomer and editor of the journal Monatliche Correspondenz zur Beförderung der Erd- und Himmels-Kunde, when he sent letters out to a select group of astronomers, asking them to dedicate themselves to a search for a "missing planet". The leadership of the group was undertaken by Wilhelm Olbers, who himself would discover numerous objects and formulate what is called Olbers' Paradox. The Titius–Bode law had predicted a planet to be found in orbit between Mars and Jupiter, where none was then found. This gave the group a location to concentrate their search. Just as the group was forming, Italian Giuseppe Piazzi discovered Ceres, the largest object in the region that would later be named the asteroid belt. Over the next several years, the group found and identified three more objects in similar orbits, which were named Pallas, Juno, and Vesta. After discovering such a large number of relatively small objects in a similar orbit, it became clear that no planet-sized object likely existed in that region. The group members' interest waned in the search. Additionally, the Napoleonic Wars had disrupted the work of several group members, especially when the war came to Lilienthal, Lower Saxony, whose observatory served as the home for many of the scientists working with the celestial police. It would be another generation before any further major discoveries of planets (or even large asteroids) occurred.[2][3][4][5]
Members
The name "celestial police" is generally assigned to the group of 24 men invited by Franz Xaver von Zach (and including himself) to participate in the search for additional planets in the region that would later be named the asteroid belt. Not every one of these invitees actively participated in the search, and others who worked on the problem, often alongside members of the celestial police, such as Friedrich Bessel, are not included in the group. The canonical list of 24 members of the celestial police are (as organized by primary residence):[6][5]
- Germany
- Johann Elert Bode
- Johann Sigismund Gottfried Huth
- Georg Simon Klügel
- Julius August Koch
- Johann Friedrich Wurm
- Ferdinand Adolf Freiherr von Ende
- Johann Gildemeister
- Karl Ludwig Harding
- Heinrich Wilhelm Matthias Olbers
- Johann Hieronymus Schröter
- Franz Xaver von Zach
- Austria
- Denmark
- Sweden
- Russia
- France
- England
- Italy
Tasks
The primary task for the celestial police was the systematic survey of the sky near the ecliptic, so as to find a small planet that was expected to exist between the orbits of Mars and Jupiter. The existence of such a body followed from the Titius-Bode law, a geometric series of the orbital radii from Mercury to Uranus, which has a gap at 2.8 astronomical units. Even Kepler had postulated such an undiscovered planet in his Harmonices Mundi.
The second task was to improve the star catalogues, which was necessary to make a positive identification of new objects and to derive their exact orbits.
The observatories involved in the organisation were distributed across all larger European countries with a concentration in Germany, Austria and Italy. Some observatories were provided by the celestial police, which was founded, amongst others, by Franz Xaver von Zach and Johann Hieronymus Schröter.
The search by the celestial police was coordinated by dividing the area surrounding the ecliptic into 24 sectors.[7] Each sector was allocated to an observatory, which would conduct the search for the planet in its sector. Wilhelm Olbers, discoverer of minor planets (2) Pallas and (4) Vesta, and Lalande argued in favour of wider search areas in part of the sky.
The search for the first minor planet
The founding of the organisation was initiated by the German-Austrian astronomer Franz Xaver von Zach, who had also organised the first congress of astronomers in 1798 in Gotha, and the astronomer Johann Hieronymus Schröter, who had built a very well equipped observatory in Lilienthal (north of Bremen). From the start, a dozen European observatories participated to look for the additional planet postulated by Johannes Kepler.
The founding of the research group also has to do with the limited means of communication in science, which was for the most part restricted to letter exchanges between individual scientists.
By coincidence, the first asteroid (1) Ceres was discovered at the turn from 1800 to 1801 by Giuseppe Piazzi. The first success of the group was the difficult recovery of Ceres at the end of 1801 after it had passed through superior conjunction behind the Sun. To this end, Gauss had developed the theory to derive planetary orbits from observations. Ceres was first seen again almost simultaneously by Zach (Gotha) and Olbers (Bremen). Soon afterwards, Olbers discovered (2) Pallas and in 1807 (4) Vesta; in 1804 Schröter's assistant Harding had discovered the third minor planet (3) Juno. Olbers' successes were due to his sectors being in the constellations of Virgo and Cetus.
Better star catalogues
Further research topics were discussed by the Vereinigte Astronomische Gesellschaft, which had been founded just before the celestial police. This loose association of leading astronomers had as one of its aims the compilation of more precise star catalogues and to improve knowledge of spherical astronomy and coordinate systems. Public outreach was another goal.
More precise star catalogues were required for two reasons:
- It was necessary to identify and locate the positions of fainter celestial objects than in the past.
- Sound definitions of coordinate systems were needed as basis for the precise determination of the orbits of newly discovered celestial bodies.
It was in the process of working on a more precise star catalogue that Piazzi discovered Ceres. The difficulties in tracking Ceres thereafter emphasised the need for better star catalogues.
Later tasks
Another new topic of astronomical research in the early 19th century was the surveillance of variable stars and novae. German astronomers like Argelander were particularly interested in this work. The compilation of precise star catalogues, similar to the search for minor planets 1800 to 1807, was divided into zones that were allocated to different observatories. In the event, future discoveries of minor planets and comets could draw upon such star catalogues and atlases.
The division of labour pioneered by the celestial police, around 1850, lead to the concept of surveys, also to the compilation of catalogues of nebulae. The most famous star catalogue of the 19th century is the Bonner Durchmusterung with 300,000 stars, which was later extended through the work of more southerly observatories. Already in the late 18th century, did the Messier catalogue accelerate the identification of new comets. By 1802, such catalogues had been vastly expanded by William Herschel.
Around 1900 an organisation similar to Zach's celestial police intended to find more small bodies in the solar system. The Austrian Johann Palisa organised the systematic determination of orbits of newly discovered or recovered celestial bodies, while the German Max Wolf pioneered the use of photographic surveillance methods in astronomy and discovered more than 200 asteroids in the process.
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