Glossary of watchmaking

Secular Perpetual calendar

Quantième perpétuel séculaire | セキュラー・パーペチュアルカレンダー | 长效万年历

Calibre 89 © Patek Philippe

Devised to incorporate the specificities of the Gregorian calendar. It is perpetual because it automatically adjusts to months with 30 days and to the 28 or 29 days in February. Unlike the Perpetual calendar it is also automatically adjusted for the exceptionnally non-leap year years, the next being 2100 et 2200.

See Watches with astronomical indications.