1801-2001: the bicentenary of Ceres' discovery
Ceres was the first
asteroid to be discovered in 1801, exactly 200 years ago. Before
that moment the existence of asteroids had not been foreseen...
The astronomer G. Piazzi
night Piazzi discovered Ceres by Nanni Riccobono
On January 1, 1801 Father Giuseppe Piazzi was observing for a new star catalogue a collection of the precise location of all stars visible in the sky. While observing stars in the constellation Taurus, he saw a small, starlike object that was not listed on any of his star maps. He carefully recorded its location, but on the next night, he noticed that the object had moved slightly to the east. Stars don't do such a thing. Over the next six weeks he recorded its motion, and discovered that it was moving relative to the background stars. Its rapid motion indicated that the object was not a star, but rather an object in the solar system.
The first asteroid was discovered. Piazzi had discovered Ceres, the largest known asteroid (roughly one-third the size of the moon). Three more asteroids were discovered just years after--Pallas in 1802, Juno in 1804, and Vesta in 1807. Asteroid discoveries were rare from then until 1891, when photographic search methods were first introduced.
click here for the full story
the missing planet? by Livia Giacomini
this law, however, there seemed to be a gap at 2.8 A.U.,
where a missing planet should have existed. At the end of
the year 1800, a search for this missing planet was to be
organized, when the first asteroid was found by Giuseppe
Piazzi and named after the patron goddess of Siciliy,
Ceres. Ceres was first believed to be the missing planet
that could confirm Titus Bode's law. But very soon other
bodies were discovered in the same region (Pallas in
1802, Juno in 1804 and Vesta in 1807). It soon became
clear that Titus-Bode's law had to be refused, and
between Mars and Jupiter, not just one, but many minor
planets had to exist (in what is today called the
asteroid's main belt).