Die Wiederauffindung der Ceres im Jahre 1801; Die Wiederauffindung der Ceres im Jahre 1801; The rediscovery of Ceres in 1801.

After the discovery by Piazzi, the first known asteroid disappeared in February 1801 in the daylight sky. Its rediscovery was the result of the combined efforts of a theoretician (Gauß) and a practitioner (Zach). The factual rediscovery took place at the end of 1801: Zach got the first sight of Ceres on December 7 and gained the insight of its planetary nature on December 31. He was succeeded by Olbers, whose corresponding dates were January 1 and 2 of 1802.