MISSION
Background Part 3
The discovery of Uranus in 1781, close to the location predicted by the Titius-Bode law of proportionality, persuaded Baron Franz Xaver von Zach, the court astronomer at Gotha to search for the proposed missing planet between Mars and Jupiter. Not unreasonably, he limited his investigation to the Zodiac, and believing that only a methodical search offered hope of success, he produced for himself a catalogue of zodiacal stars arranged by right ascension; but without success. In the autumn of 1799 the idea of a cooperative attack on the problem emerged:
It was the opinion of these men of discernment, that to get onto the trail of this so-long-hidden planet, it cannot be a matter for one or two astronomers to scrutinise the entire Zodiac down to the telescopic stars.
It was on 21 September the following year that the cooperative attack - probably without precedent in the history of science - became a reality. On that day six astronomers met in Lilienthal: von Zach himself; J.H. Schröter, the chief magistrate of Lilienthal, whose world-famous collection of instruments included a Herschel reflector of 27ft focal length; H.W.M. Olbers, physician from nearby Bremen and longtime collaborator with Schröter; C.L. Harding, who was employed by Schröter and who was himself to discover the third asteroid in 1804; F.A. Freiherr von Ende; and Johann Gildemeister. They decided that even six observers were too few for the task ahead, and nominated instead a group of twenty-four practicing astronomers chosen from throughout Europe. Schröter was to be president and von Zach, secretary. The entire Zodiac was divided up into twenty-four zones each of 15 degrees in longitude, and extending some 7 or 8 degrees north and south of the ecliptic in latitude. The zones were allocated to the members by lot. Each member was to draw up a star chart for his zone, extending to the smallest telescopic stars. Accordingly von Zach sent out the invitations to join this society of celestial cops. Shortly thereafter on January 1, 1801 Guiseppe Piazzi of Palermo discovered the first asteroid, 1 Ceres, but, ironically, despite the methodical approach of von Zach and his colleagues, Piazzi was not an original member of the celestial cops. They had been scooped by a lone observer.
Note: Some of this information was excerpted from Bode's Law and the Discovery of Ceres by Michael Hoskin, Churchill College, Cambridge.
- Vesta: A Brief Review of Current Knowledge by K. Tschann-Grimm (PDF)
- Asteroids 2001: From Piazzi to the 3rd Millennium
- Meteorite: International Quarterly of Meteorites and Meteorite Science
- The Minor Planet Observer
- Background Part 2: Why is There Such a Large Gap Between the Orbits of Mars and Jupiter?
