Alfonsine tables

[5] The methods of Claudius Ptolemy were used to compute the table, dividing the year into 365 days, 5 hours, 49 minutes, 16 seconds—very close to the currently accepted figure.

[6] (There is a famous (but probably apocryphal)[7] quote attributed to Alfonso upon hearing an explanation of the extremely complicated mathematics required to demonstrate Ptolemy's geocentric model of the solar system: "If the Lord Almighty had consulted me before embarking on creation thus, I should have recommended something simpler.")

Nicolaus Copernicus, known as the father of modern astronomy, bought a copy while at the University of Cracow, and cared about it enough to have it professionally bound with pieces of wood and leather.

[9] Alexander Bogdanov maintained that these tables formed the basis for Copernicus's development of a heliocentric understanding in astronomy.

Copernicus's publication, De revolutionibus, was not easy to use and the Prutenic tables were intended to make the heliocentric model more usable by astrologers and astronomers.