Tycho's lunar theory
Tycho's distinctive contributions to lunar theory include his discovery of the variation of the Moon's longitude. This represents the largest inequality of longitude after the equation of the center and the evection. He also discovered librations in the inclination of the plane of the lunar orbit, relative to the ecliptic (which is not a constant of about 5° as had been believed before him, but fluctuates through a range of over a quarter of a degree), and accompanying oscillations in the longitude of the lunar node. These represent perturbations in the Moon's ecliptic latitude. Tycho's lunar theory doubled the number of distinct lunar inequalities, relative to those anciently known, and reduced the discrepancies of lunar theory to about 1/5 of their previous amounts. It was published posthumously by Kepler in 1602, and Kepler's own derivative form appears in Kepler's Rudolphine Tables of 1627.
Although Tycho's planetary model was soon discredited, his astronomical observations were an essential contribution to the scientific revolution. The traditional view of Tycho is that he was primarily an empiricist who set new standards for precise and objective measurements. This appraisal originated in Pierre Gassendi's 1654 biography, Tychonis Brahe, equitis Dani, astronomorum coryphaei, vita. It was furthered by Johann Dreyer's biography in 1890, which was long the most influential work on Tycho. According to historian of science Helge Kragh, this assessment grew out of Gassendi's opposition to Aristotelianism and Cartesianism, and fails to account for the diversity of Tycho's activities.
Tycho considered astrology to be a subject of great importance. In addition to his contributions to astronomy, he was famous in his own time also for his contributions to medicine; his herbal medicines were in use as late as the 1900s.
Although the research community Tycho created in Uraniborg did not survive him, while it existed it was both a research center and an institution of education, functioning as a graduate school for Danish and foreign students in both astronomy and medicine. Tycho's success as a scientist also depended on his adroit political skills, to obtain patronage and funding for his work.
HEAT1X-TYCHO BRAHE is the name of a manned private spacecraft to be launched by Copenhagen Suborbitals. Other things named after him include a bar in Zagreb and a ferry operating between Sweden and Denmark.