His method involved three observations taken at equal intervals and he assumed that the comet followed a parabolic path so that he ended up with more equations than there were unknowns.
Kanyang paraan kasangkot tatlong kuha obserbasyon at pantay na pagitan at siya assumed na ang buntala sinundan ng isang paparabola path na kaya siya natapos equation na may higit pa kaysa doon ay unknowns.