observerly’s lightweight, zero-dependency, type-safe astrometry library for TypeScript. Accurately determine the positions of the Sun, Moon, and planets, handle coordinate transformations with ease, calculate transit times for any celestial object, and integrate precision astronomy into your projects with clean, dependency-free code.

Quantum's interactive calendars, e.g. French Republican Calendar using historic equinox method for leap years.

Master the seasons with the Milesian calendar. Conversion and display JS routines.