Tycho Brahe was the last major observational astronomer to work
without a telescope; he used sextants and quadrants. Actually, in
Astronomiæ Instauratæ Mechanica Brahe
described more than a couple dozen astronomical instruments that
he used or designed. Galileo Galilei introduced the use of
telescopes into astronomy in 1610.
Tycho Brahe the man is known for his geo-heliocentric model
of the solar system, and for a duel during which he lost his nose.
See also in The book of science:
Readings on wikipedia: