Comparison
Astreya vs Co-Star
A factual, feature-by-feature comparison of two very different approaches to modern astrology apps.
| Feature | Astreya | Co-Star |
|---|---|---|
| Ephemeris engine | Swiss Ephemeris (JPL DE431) | NASA JPL (proprietary layer) |
| House system | Placidus (Western), Whole Sign (Vedic) | Placidus, not user-selectable |
| Chiron | JPL Horizons + cubic-Hermite (<0.01°) | Included, method undisclosed |
| Vedic astrology | Yes - Lahiri, Nakshatras, Vimshottari Dasha | No |
| Human Design bodygraph | Yes - full type/strategy/authority/profile/gates/channels | No |
| Numerology | Yes - Pythagorean, master numbers | No |
| Tarot readings | Yes - Rider-Waite-Smith spreads | No |
| Dream dictionary | 1800+ symbols, Jungian framing | No |
| PDF export | Yes | No |
| Data privacy | Your data stored on your account only; no social graph | Friends graph, notifications |
| Languages | Bulgarian + English | English |
| Free tier | Free chart + previews; paid deep reports | Free app + paid add-ons |
Which app should you pick?
Choose Co-Star if you want a low-friction daily prompt and a friends feed. Choose Astreya if you want your actual natal chart with houses, aspects, transits, a Human Design bodygraph, Vedic dashas, numerology, tarot spreads and a searchable dream dictionary - with the underlying method (Swiss Ephemeris, Placidus, Lahiri, JPL Horizons) documented on the about page.
FAQ
Is Astreya more accurate than Co-Star?
For the underlying planetary math both apps use ephemerides — Co-Star sources from NASA JPL, Astreya from Swiss Ephemeris (which itself derives from JPL DE431). Where Astreya adds precision is in extras Co-Star omits: Placidus houses, Chiron via JPL Horizons with cubic-Hermite interpolation, IAU 2006/2000A precession/nutation, and Lahiri-based Vedic sidereal conversion.
Does Astreya replace human interpretation with AI?
No. Astreya's readings are drafted by the Editorial Team using deterministic calculations, then reviewed before publication. Optional AI-assisted narratives are clearly labeled and always sit on top of the same verified numbers.
Which app is better for beginners?
Co-Star for playful daily notifications; Astreya for people who want the actual chart, houses, aspects, Human Design bodygraph, Vedic dashas and a downloadable PDF report.
Does Astreya offer Human Design like Co-Star?
Co-Star does not include Human Design. Astreya calculates the full bodygraph (type, strategy, authority, profile, 9 centers, 36 channels, 64 gates) using the official Ra Uru Hu method.