Why were Tycho Brahe's measurements of Mars especially useful to Johannes Kepler?

Tycho Brahe’s observations of Mars were uniquely valuable to Johannes Kepler for several critical reasons:

• High Eccentricity: Mars possesses one of the most eccentric orbits in the solar system. Because its path deviates significantly from a perfect circle, these departures are much easier to detect than those of planets with more circular orbits, such as Earth.12
• Observational Accuracy: Tycho Brahe’s data were the most precise naked-eye measurements available before the invention of the telescope. Kepler believed these observations were accurate to within 2 minutes of arc, a level of precision that allowed him to identify discrepancies in existing models.13
• Model Refinement: When Kepler attempted to fit Mars into traditional circular models, he could not reconcile the theory with Tycho’s data to better than 8 minutes of arc. This persistent gap forced Kepler to abandon the assumption of circular motion and ultimately led him to discover that planets move in ellipses with the Sun at one focus.124

By analyzing these records, Kepler was able to move beyond the limitations of the Ptolemaic and Copernican systems to establish his laws of planetary motion.154