AstroWatch — Calculation · Zodiac · Houses · Nodes
If the numbers matter to you, start with the source. AstroWatch computes every chart with the Swiss Ephemeris 2.10 — the DE431-derived engine trusted across professional astrology — accurate to the arcsecond, with 28 house systems, tropical and sidereal frames, and full offline calculation on Windows.
AstroWatch exposes the whole engine. Choose your frame of reference, house division and node model — then trust the numbers.
DE431-derived, arcsecond accuracy across the supported range.
Placidus, Koch, Whole Sign, Regiomontanus, Campanus, Gauquelin and more.
Two zodiacs and 8 ayanamsas — Lahiri, KP, Fagan/Bradley, Raman and more.
Three Lilith models, geocentric or topocentric parallax.
Automatic handling beyond ±66° where some systems break down.
Bundled datasets — charts calculate with or without a connection.
Install free from the Microsoft Store and check the positions yourself. Unlock the full engine with a one-time Pro licence.
The Swiss Ephemeris is a high-precision astronomical calculation engine derived from NASA JPL's DE431 data, trusted across professional astrology software. AstroWatch uses version 2.10, computing planetary positions accurate to the arcsecond across the supported date range.
28 house systems, including Placidus, Koch, Whole Sign, Regiomontanus, Campanus and Gauquelin sectors, with automatic high-latitude fallback beyond ±66 degrees where some systems break down.
Yes. The Swiss Ephemeris runs locally on your device with bundled datasets, so charts calculate with or without an internet connection. AstroWatch is local-first — your charts live on your device, not on a server.
AstroWatch is free to install and cast charts. The Pro licence is a one-time purchase of $128.99 (launch price) that unlocks the full engine — all house systems, sidereal zodiacs, the timing engine and exports — with free lifetime updates.