When tycho observed the new star of 1572, he could detect no parallax. why did that undermine belief in the ptolemaic system? in the perfect heavens idea of aristotle? it indicated that the new star did not have a circular epicycle required by the ptolemaic model and the perfect heavens of aristotle. it indicated that the new star was far enough away to be part of the celestial sphere, which was perfect and changeless in both the ptolemaic model and the perfect heavens of aristotle. it indicated that the new star was not a sphere, which contradicted the perfect geometrical forms required by the ptolemaic model and the perfect heavens of aristotle. tycho did detect parallax, which convinced him that earth moved and caused him to believe in the copernican system.