Background
Knorre was born in Dorpat, Russian Empire in present-day Estonia, the son of Ernst Friedrich Knorre, a German-born astronomer, and his wife Sophie (née Senff).
Knorre was born in Dorpat, Russian Empire in present-day Estonia, the son of Ernst Friedrich Knorre, a German-born astronomer, and his wife Sophie (née Senff).
University of Tartu.
Recently National Aeronautics and Space Administration named an asteroid in honor of the three generations of Knorre astronomers. Although Knorre"s father died in 1801 when he was just 9 years old, the elder scientist"s career as a professor of mathematics at the Universität Dorpat where he was also chief Observator for the Dorpat observatory, had already made a strong impression on the young boy who applied himself enthusiastically to the study of math and science. Knorre was determined to continue in his father"s footsteps as an astronomer, taking up the bulk of his unfinished work, but Senff felt that the clergy was a more secure means of self-support for a poor orphan, and urged him to study theology.
Although he dutifully entered into the divinity program, Knorre still managed to attend several astronomy lectures and became devoted to the subject, largely educating himself in the ensuing years.
He eventually availed himself to the new head of the observatory, Wilhelm Struve, who agreed to accept Knorre as an assistant. Under Struve"s tutelage, Knorre had the opportunity to acquire a decisive experience in geodesy and had earned such esteem by the age of nineteen that Struve recommended him to Admiral Aleksey Greig who was looking for "a young and intelligent astronomer, able to help him to equip an observatory in Nikolayev on the Black Sea."
The challenge for Knorre was the equipment of the observatory.
He asked for a business trip to tour the other important observatories of Europe, and when Greig agreed, set off on a journey by stagecoach that was to take more than two years. In Germany, he visited Friedrich Bessel, Johann Franz Encke, and Heinrich Christian Schumacher and, in Paris, he called on François Arago.
From there he also went to both Greenwich and Dublin, largely in pursuit of manufacturers of good chronographs.
Back home he discussed with admiral Greig his impressions and ordered the equipment for the observatory. In his equipment there was a mercuric artificial horizon mirror. To exclude measurement failures it was possible to look with the telescope direct to the stars or indirect via the mercurial mirror.
He moved to Berlin in 1862 to study astronomy.
He died there in 1883.
Russian Academy of Sciences]
Knorre was member of the Royal Astronomical Society.