In the Gregorian calendar, the length of the mean tropical year is implicitely defined as 365 + 97/400 solar days. The present work is a contribution to the studies on the origin of the fraction 97/400. We assume that the reform used the experimental value of the tropical year given in the Alphonsine Tables. Then we show that a direct computation of two best rational approximations of the fractional part r = 5h49′16′′ of the Alphonsine year, together whith a simple interpolation formula well–known to old calendarists, would have given precisely the fraction 97/400.

On the origin of the 97/400 leap years rule in the Gregorian calendar

INVERNIZZI, SERGIO;
2011-01-01

Abstract

In the Gregorian calendar, the length of the mean tropical year is implicitely defined as 365 + 97/400 solar days. The present work is a contribution to the studies on the origin of the fraction 97/400. We assume that the reform used the experimental value of the tropical year given in the Alphonsine Tables. Then we show that a direct computation of two best rational approximations of the fractional part r = 5h49′16′′ of the Alphonsine year, together whith a simple interpolation formula well–known to old calendarists, would have given precisely the fraction 97/400.
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/2382201
 Avviso

Registrazione in corso di verifica.
La registrazione di questo prodotto non è ancora stata validata in ArTS.

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact