AR00.space

Why "AR00"?

AR00 stands for Ascensione Retta 00h 00m — the celestial coordinates of the Vernal Equinox (the First Point of Aries, γ), the origin of all equatorial coordinate systems. It is the zero-point from which we measure the sky. It felt like the right name for a project that started from zero, too.

This project has roots that go back decades. As a teenager, my very first program — written in GW-BASIC and saved on a 3.5″ floppy disk — calculated sunrise and sunset times. I still remember my father dictating the code listing while I typed it on my Olivetti M80.

Since then, I've always had the itch to build my own astronomy library, drawing from all those books on astronomy I'd collected over the years. Life got in the way for a while — but now, finally, a small dream is fulfilled. 🔭

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AstroCalc implements classical computational astronomy algorithms from authoritative sources:

• Jean Meeus — "Astronomical Algorithms" and "Astronomical Formulae for Calculators"
• USNO — U.S. Naval Observatory Almanac algorithms
• Lieske (1979) — Precession of the equinoxes
• VSOP87 — Planetary position theory