Real astronomy.
Not guesswork.
Every number you see on Starogram is computed from the same data sources used by NASA mission planners, ESA spacecraft, and professional observatories worldwide.
Where every number comes from
No black boxes. Every planetary position, moon phase, and eclipse date traces back to peer-reviewed astronomical data.
Planetary positions built from decades of radar ranging, spacecraft tracking (Viking, Pathfinder, MRO), and Apollo lunar laser ranging. Accurate to ~10 meters for inner planets.
Lunar positions from centuries of observational data and laser ranging via Apollo retroreflectors. Moon distance accurate to within 1 meter.
Star positions and magnitudes from ESA’s astrometry satellite (1989–1993). Positional accuracy: 1–2 milliarcseconds. J2000.0 epoch coordinates.
Solar and planetary positions computed from Variations Séculaires des Orbites Planétaires. Used for real-time sunrise, sunset, and solar transit calculations.
Every solar and lunar eclipse from 1901–2100, compiled by Fred Espenak & Jean Meeus. Timing accurate to within seconds.
Galaxies, nebulae, and star clusters with J2000.0 coordinates. Real-time altitude and azimuth for your observer location.
10 celestial bodies. 12 houses. Precise aspects.
Enter your birth date, time, and location. The system computes exact planetary positions as they appeared from your coordinates at that moment. Houses are calculated with the Placidus system — the most widely used in Western astrology. Your Ascendant is the exact ecliptic degree rising on the eastern horizon at your birth.
Moon & Sun in real time
Moonrise, moonset, illumination, zodiac sign, and visual tilt angle — all computed for your specific city, accounting for standard atmospheric refraction (−0°34′). What you see reflects the actual sky above you right now.
Compatibility beyond Sun signs
Personal compatibility overlays two complete birth charts and analyzes planet-to-planet aspects — how your Moon relates to their Venus, your Mars to their Jupiter. Each aspect uses calibrated orbs: 1.5° personal, 2.0° social, 1.0° generational planets.
Every number is verifiable
We show exact degrees, house placements, and aspect orbs — not simplified summaries. The calculations are deterministic: same input, same output. Cross-check against JPL Horizons or the US Naval Observatory anytime.
- ✓Exact degrees and house placements shown in every chart
- ✓Missing birth time? We tell you what’s missing, not guess
- ✓Deterministic: identical inputs always produce identical results
- ✓Independently verifiable against any standard ephemeris
Frequently Asked Questions
Where does the astronomical data come from?
Planetary positions are computed from NASA JPL’s Development Ephemeris (DE431), built from radar ranging, spacecraft tracking, and lunar laser ranging. Lunar detail comes from the ELP2000 ephemeris (Bureau des Longitudes, Paris). Eclipse data is from NASA GSFC’s Five Millennium Canon. Star positions use the ESA Hipparcos catalog.
How accurate are the calculations?
Planetary positions are accurate to approximately 10 meters for inner planets. Lunar distance precision is within 1 meter. Eclipse timing is accurate to within seconds. These are the same data sources used by professional observatories and space agencies worldwide.
Is the content AI-generated?
Astrological interpretations combine traditional astrological knowledge with AI-assisted writing, then are reviewed for accuracy and depth. The astronomical calculations behind every interpretation are purely mathematical — computed from ephemeris data, not generated.
Why does birth time matter?
The Earth completes one rotation every 24 hours, so the Ascendant shifts approximately every 2 hours. Without accurate birth time, the Ascendant, house placements, and exact lunar degree cannot be determined — all of which significantly shape chart interpretation.
Can I verify the calculations independently?
Yes. Cross-check our planetary positions against the JPL Horizons online system (NASA). Moon phases and eclipses can be verified against US Naval Observatory data. The calculations are deterministic — identical inputs always produce identical results.
See it in action
Build your birth chart from real astronomical data. Free, instant, no sign-up needed.