Comes, Mercè (Comes Maymó), 1949-20102016-04-282016-04-2820011576-9372https://hdl.handle.net/2445/97991The aim of trepidation models was to account for two phenomena that puzzled medieval astronomers: the secular decrease of the obliquity of the ecliptic, and the apparent changes in the velocity of precession over the years.118 p.application/pdfengcc-by-nc-nd (c) Comes, Mercè (Comes Maymó), 1949-2010, 2001http://creativecommons.org/licenses/by-nc-nd/3.0/esAstronomia àrabAstronomia antigaAstronomia medievalArab astronomyAncient astronomyMedieval astronomyinfo:eu-repo/semantics/article1958852016-04-28info:eu-repo/semantics/openAccess