He gave private lessons in mathematics and Latin to other pupils of his school and even to adults, earning enough money to help his impoverished mother to pay for his education.

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 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.