This webpage is part of www.janzuidhoek.com, which is a website promoting [Jan Zuidhoek
(2021) Reconstructing Metonic 19-year Lunar Cycles
(on the basis of NASA’s Six Millennium Catalog of
Phases of the Moon): Zwolle], and concerns this
groundbreaking book, which is available via this website, and its author Jan Zuidhoek.
Book and Author
This book explains, by following the
mainstream of the history of the computus paschalis developed from early in the third century for the
purpose of determining (Alexandrian or Julian calendar) dates of Paschal Sunday
which rised shortly after AD 250 in Alexandria
(Egypt) to ultimately in AD 1582 (turning point in the history of
chronology) flow into a more realistic method for determining (Gregorian
calendar) dates of Easter, how at the time dates of Paschal Sunday depended on
phases of the moon and how recently both lost Metonic
19‑year lunar cycles constructed in Alexandria before the council of Nicaea in AD 325 (turning point in the history of
Christianity) were reconstructed on the basis of NASA’s Six Millennium Catalog of Phases of the Moon.
The author of this groundbreaking
book was born in 1938, studied mathematics, physics, and astronomy at the
university of Utrecht from 1960
to 1969, and was a teacher of
mathematics from 1970 to 2001 at the Gymnasium Celeanum
in Zwolle. After having gone deeply into the history
of mathematics, chronology, and early Christianity, ultimately resulting in his
lucid webpage “Christian Era and Universal Time”, he became fascinated by the
Alexandrian computus. In 2009 he succeeded, by using
the Six Millennium Catalog, in determining the Metonic 19‑year lunar cycle underlying the legendary
19‑year Paschal cycle of the famous third century Alexandrian computist Anatolius contained in
the fourth or fifth century Latin text De
ratione paschali. The
presentations he gave at the international conferences on the science of computus at the university of Galway in 2010 and 2018
resulted in 2017 in a pioneering article entitled “The initial year of De ratione paschali and the relevance of its paschal dates” and in
2019 in the first edition of this book reducing that article to a preparatory
study.
© Jan Zuidhoek 2019-2022