by Hermetic Systems Adds a number of days to a date, calculates the number of days between two dates, and converts among dates in various solar calendars: Gregorian, Julian, ISO 8601 Week, Hermetic Leap Weak and day-in-year (yyyy-ddd).
by Hermetic Systems A program to search for eclipses (lunar, solar, total, annular and umbral), to calculate the phase of the Moon at any given date and time and to convert between dates in the Gregorian and Julian calendars and dates in four lunar calendars.