As a young man, he left home with his elder brother Johann to study theology at the University of Halle, where the two also secured positions as private tutors.

At that time, the city of Dorpat had no university, and Knorre had little support in his scholastic pursuits, but he nevertheless undertook a daily record of his work, making regular entries about his celestial observations in his journal as early as 1795.

[1] With Knorre's measured success in astronomy came an ever-increasing sense of influence among Dorpat's scientific community, and as his affiliations grew, so too did his recognition among political circles.

They sought shelter with Sophie's brother, himself a widower, Karl August Senff, who taught painting at the Fine Arts Department in the university.

As a young teen, Karl gave private lessons in mathematics and Latin to other pupils at his secondary school, and even to many adults, not only earning enough money to pay for his own education, but also securing his own place at the university at the age of 15.