Almanac 历

A C implementation of most of the book "Calendrical Calculations".

Early Modern Dates

Julian date calculations and calendar conversions for Swift.

An Orthodox and Catholic Easter Date Calculator

A Swift framework containing an astronomical model of the Moon, including properties to obtain the age, percent illuminated, phase, transitions, and other properties of the Moon at a point in time. This is a Swift port of John Walker's `moontool.c`, originally written in 1987.

Convert between Julian day numbers and Julian & Gregorian calendars

A Windows console application that evaluates mathematical expressions involving multiple operators and functions.

jcalendaR is a package for converting between current Japanese calendar, old Japanese calendar that Kyureki, and Julian and (proleptic) Gregorian calendar in R.

Orthodox and Oriental Orthodox saints, name-days, liturgical readings, moon phases, and ICS feeds — FastAPI · React · 17 traditions · GitHub Pages

Converts a gregorian date to julian date.

Historic calendars of Europe

The project is a collection of functions to convert dates between Gregorian and Julian calendars. Additionally it includes functions to calculate Orthodox and Catholic Easter dates.

Calendar implementation using object-oriented principles in C++.

An implementation of the Roman calendar post-Julian reforms (46 BC)

Julian Date gadget for Windows. main branch: https://barionleg.github.io/JulianDate/source/Julian.html

An old code, written for embedded devices, thinked for calculate the sunset and sunrise time. It also have so many interesting calendar functions.

Selected development examples from Numerical Recipes in FORTRAN 77