Discovery of the 100th minor planet 1868

The number of asteroids with known orbit was 410810 in July 2014. With such a large number it is no wonder that a new asteroid will only get attention if its path crosses that of Earth, and has the chance to hit it once. It was not always this way, in the mid-1800s even a commemorative medal has been issued to the occasion of the discovery of 100th asteroid.

That should be a planet between Mars and Jupiter's orbit has emerged in the eighteenth century, thanks to the work of two astronomers. The rule is - which was later named after the two astronomers - Titius-Bode law as we know. Whether there is any physical content behind the rule, or merely a coincidence, today is still unclear, but when Uranus was discovered by William Herschel in 1781, the new planet's orbit followed the Titius-Bode law. This discovery also gave a push to start searching after the unknown planet. 

The foundation of astronomical association in Lilienthal

Enforced by the success of astronomical meeting Zach and his German astronomer friends initiated to establish an astronomical association. For the founding conference Schröter's observatory in Lilienthal was chosen. The meeting took place between 13-20, September 1800. The association founders were: Ferdinand Adolf von Ende, Johann Gildemeister, dr. Heinrich Wilhelm Matthias Olbers, Karl Ludwig Harding, von Zách and Johann Hieronymus Schröter.
The participants intended their association to be international, and by common accord the next astronomers were invited to be a member:
Johann Elert Bode, Berlin; Joseph Tobias Bürg, Wien; Thomas Bugge, Copenhagen; J. C. Burckhardt, Paris; Wilhelm Herschel, Slough, Windsor; Prof. Hurth, Frankfurt am Oder; Georg Simon Klügel, Halle; dr. Koch, Danzig; Nevil Maskelyne, Greenwich; Prof. Melanderhjelm, Stockholm; Pierre Méchain, Paris; Barnaba Oriani, Milan; Joseph Piazzi, Palermo; Schubert, Saint Petersburg; Prof. Sniadecki, Krakko; Charles Thulis, Marseille; Johann Friedrich Wurm, Blaubeuren; Ferdinand von Ende, Celle; Johann Gildemeister, Bremen; Karl Ludwig Harding, Lilienthal; Prof. Svanberg, Uppsala; Wilhelm Olbers, Bremen; Johann Hieronymus Schröter, Lilienthal; von Zách, Gotha.
The listed names can be found among the authors of AGE and its successor the Monatliche Correspondenz, published since January 1, 1800.

The newly formed astronomical association aimed the following tasks:

  • full exploration of the sky between the planets Mars and Jupiter to find previously supposed unknown planet;
  • to search for comets only visible in telescopes, quickly identify of track parameters and to make them available to other researchers;
  • determination of the parallax of fixed stars;
  • search for variable stars;
  • In order to prepare a better than ever star chart introduce astronomers' work with their peers and establish a working relationship among them using the Monatliche Correspondenz.

The six astronomers gathered in Lilienthal, as we see, had a carefully designed program, and assessed future tasks of astronomy correctly. It was only a joke of fate that the so wanted planet, that later received the name Ceres, was found by astronomer Piazzi in Palermo, by accident on January 1, 1801.


Vargha Domokosné : Zách János Ferenc (1754–1832) Csillagász, Hungarian

The fact that by the end of the 1700s astronomers still have not been able to find it, they have attributed to the possibly small size of planet and the low brightness. This also meant that a systematic search was necessary to find it in the ecliptic densely star-studded region. Lacking of reliable star maps only one method was left: that the observer registers the exact position of the stars of a given region of the sky through a telescope and then on the next night compares the scene with the drawing. If between the two observation something seems to move away, it may be an unknown planet. Such a thorough and painstaking work could only be performed by joining many - whether amateur or professional - astronomers. Then entered the scene Baron Franz Xaver von Zach, the   Hungarian astronomer, the excellent organizer and director of the Seeberg observatory. In 1798, von Zach has already successfully organized an international astronomer meeting, and the success of that forced him to form a new association in September 1800 in Lilienthal, which they called among themselves as Celestial Police (Himmelspolizei). On the foundation, see sidebox.

The discovery of asteroids was uneven and slow, sometimes accidental, sometimes it was the fruit of diligent work. It took 68 years to find the hundredth. The discovery was so significant that in France at the Paris Mint a medal was issued to remember it. The medalist was the famous engraver Apheé Dubois. On the obverse of the xx mm diameter bronze medal is an allegorical female figure with her right hand showing to a small spherical asteroid among the stars. Beneath the Earth, with France and Germany to us. The name of these two countries can be read on the medal. The legend around: "CENT PLANETÈS DÉCOUVERTES ENTRE MARS ET JUPITER 1801 - 1868", that is the discovery of the 100th planet between Mars and Jupiter.

olbers 100. kisbolygo obverseBelow three names can be found, let's look at these. The first asteroid, Ceres was found by accidently by an Italian astronomer Giuseppe Piazzi, on January 1, 1801. His name was therefore in the first place. Before his name the date of the discovery can be read.

The second name is Olbers. Heinrich Wilhelm Olbers a medical doctor and amateur astronomer discovered the second asteroid Pallas on March 28, 1802. The third minor planet was discovered on September 1, 1804 by the German astronomer Karl Ludwig Harding, but his name can not be found on the medal. The fourth asteroid, Vesta was also found by Olbers on March 29, 1807. After that however the series of discovery was stopped for almost 40 years.

The Association in Lilienthal has reached its goal. The international astronomer organization was ahead of its time, and though it was broken up in 1815 in the belief that no more asteroid to be discovered, the members remained in friendly connections with each other. Fortunately, not everyone believed that no further asteroids to discover. Karl Ludwig Hencke, a German postmaster and amateur astronomer began to search for new asteroids his own observatory in 1830. His research was carried out steadily and after 15 years of failure on December 8, 1845 fortune finally smiled at him and he discovered the fifth minor planet Astræa, and the sixth on July 1, 1847. Perhaps his remarkable persistence and the fact that the discovered asteroids have given new impetus to research owes his name to a third-place on the obverse of the medal.

olbers 100. kisbolygo reverseOn the reverse left-facing portraits of three astronomers was placed. The first is John Russell Hind, who discovered 10 asteroids. Hermann Mayer Salomon Goldschmidt discovered 14, Karl Theodor Robert Luther dicovered 24, although only 16 fall into the first hundred, as he remained successful discoverer after 1868. They led the discoverers' rankings in 1868, during the time of 100th asteroid discovery. Later, there were even more successful explorers, and after 1891, when Max Wolf introduced the photographic asteroid research, more success followed. Wolf himself found 248 asteroids. Since then, the search for asteroids performed automatic telescopes and software. Their number has exceeded 400 thousand at the time of article writing, but only this medal commemorates the discoverers.