Calculation benchmark
The result table, including the caveats.
A frozen comparison of PathFinder's deterministic output with NASA JPL Horizons, Swiss Ephemeris, and named IANA time-zone rules. Every measured row is below; none of this tests astrological interpretation or event prediction.
Reproducibility boundary
Public evidence, private runner
The inputs, external references, tolerances, raw PathFinder outputs, errors, methodology, and MIT-licensed data are public. The PathFinder calculation runner and its CI repository are private, so a stranger can independently rerun the JPL and Swiss reference queries and audit this table, but cannot inspect or execute the PathFinder runner from source. We do not call this fully independent-source reproducibility.
Method
Frozen before measurement
Planet rows use the shortest circular difference from JPL Horizons observer quantity 31: apparent geocentric longitude in the true ecliptic of date. The Sun through Pluto use a 60-arcsecond floor; Chiron retains its separately certified 1,800-arcsecond floor.
House rows compare every cusp with Swiss Ephemeris 2.10.03. The polar case requests Placidus and truthfully reports PathFinder's Porphyry fallback. Timing rows cover all three Mercury crossings of 20° Aries in the 2024 retrograde loop plus Mercury, Saturn, and Pluto stations. Civil-time rows resolve named IANA zones rather than accepting numeric offsets.
References: JPL Horizons API, Swiss Ephemeris programmer documentation, and IANA TZDB.
44 raw rows
Apparent geocentric longitudes
Median error 1.86″. Largest Sun-through-Pluto error 12.77″. Chiron maximum 74.76″.
| Body | UTC instant | JPL | PathFinder | Error | Floor | Result |
|---|---|---|---|---|---|---|
| Sun | 1950-01-01 00:00:00 UTC | 280.004830° | 280.004687° | 0.51″ | 60″ | Pass |
| Sun | 2000-01-01 12:00:00 UTC | 280.368909° | 280.368739° | 0.61″ | 60″ | Pass |
| Sun | 2024-01-01 12:00:00 UTC | 280.548482° | 280.548527° | 0.16″ | 60″ | Pass |
| Sun | 2050-01-01 00:00:00 UTC | 280.748382° | 280.748509° | 0.46″ | 60″ | Pass |
| Moon | 1950-01-01 00:00:00 UTC | 61.415409° | 61.415389° | 0.07″ | 60″ | Pass |
| Moon | 2000-01-01 12:00:00 UTC | 223.323786° | 223.323891° | 0.38″ | 60″ | Pass |
| Moon | 2024-01-01 12:00:00 UTC | 161.907032° | 161.907737° | 2.54″ | 60″ | Pass |
| Moon | 2050-01-01 00:00:00 UTC | 18.675597° | 18.679144° | 12.77″ | 60″ | Pass |
| Mercury | 1950-01-01 00:00:00 UTC | 299.447252° | 299.446972° | 1.01″ | 60″ | Pass |
| Mercury | 2000-01-01 12:00:00 UTC | 271.889270° | 271.888912° | 1.29″ | 60″ | Pass |
| Mercury | 2024-01-01 12:00:00 UTC | 262.212013° | 262.210793° | 4.39″ | 60″ | Pass |
| Mercury | 2050-01-01 00:00:00 UTC | 270.059488° | 270.059741° | 0.91″ | 60″ | Pass |
| Venus | 1950-01-01 00:00:00 UTC | 316.979477° | 316.979260° | 0.78″ | 60″ | Pass |
| Venus | 2000-01-01 12:00:00 UTC | 241.565779° | 241.565233° | 1.97″ | 60″ | Pass |
| Venus | 2024-01-01 12:00:00 UTC | 243.220420° | 243.220427° | 0.02″ | 60″ | Pass |
| Venus | 2050-01-01 00:00:00 UTC | 281.248038° | 281.248592° | 2.00″ | 60″ | Pass |
| Mars | 1950-01-01 00:00:00 UTC | 182.211197° | 182.212262° | 3.84″ | 60″ | Pass |
| Mars | 2000-01-01 12:00:00 UTC | 327.963292° | 327.963899° | 2.19″ | 60″ | Pass |
| Mars | 2024-01-01 12:00:00 UTC | 267.679146° | 267.679388° | 0.87″ | 60″ | Pass |
| Mars | 2050-01-01 00:00:00 UTC | 227.714693° | 227.714707° | 0.05″ | 60″ | Pass |
| Jupiter | 1950-01-01 00:00:00 UTC | 306.505325° | 306.503535° | 6.44″ | 60″ | Pass |
| Jupiter | 2000-01-01 12:00:00 UTC | 25.253069° | 25.254200° | 4.07″ | 60″ | Pass |
| Jupiter | 2024-01-01 12:00:00 UTC | 35.584350° | 35.582853° | 5.39″ | 60″ | Pass |
| Jupiter | 2050-01-01 00:00:00 UTC | 121.691548° | 121.691524° | 0.09″ | 60″ | Pass |
| Saturn | 1950-01-01 00:00:00 UTC | 169.437422° | 169.436953° | 1.69″ | 60″ | Pass |
| Saturn | 2000-01-01 12:00:00 UTC | 40.395637° | 40.396124° | 1.76″ | 60″ | Pass |
| Saturn | 2024-01-01 12:00:00 UTC | 333.287907° | 333.286908° | 3.60″ | 60″ | Pass |
| Saturn | 2050-01-01 00:00:00 UTC | 297.574280° | 297.573249° | 3.71″ | 60″ | Pass |
| Uranus | 1950-01-01 00:00:00 UTC | 92.682721° | 92.682872° | 0.55″ | 60″ | Pass |
| Uranus | 2000-01-01 12:00:00 UTC | 314.809168° | 314.806105° | 11.03″ | 60″ | Pass |
| Uranus | 2024-01-01 12:00:00 UTC | 49.373055° | 49.373058° | 0.01″ | 60″ | Pass |
| Uranus | 2050-01-01 00:00:00 UTC | 170.732610° | 170.733582° | 3.50″ | 60″ | Pass |
| Neptune | 1950-01-01 00:00:00 UTC | 197.266039° | 197.264190° | 6.66″ | 60″ | Pass |
| Neptune | 2000-01-01 12:00:00 UTC | 303.193001° | 303.195442° | 8.79″ | 60″ | Pass |
| Neptune | 2024-01-01 12:00:00 UTC | 355.083496° | 355.086814° | 11.94″ | 60″ | Pass |
| Neptune | 2050-01-01 00:00:00 UTC | 53.603421° | 53.602663° | 2.73″ | 60″ | Pass |
| Pluto | 1950-01-01 00:00:00 UTC | 137.798381° | 137.798755° | 1.35″ | 60″ | Pass |
| Pluto | 2000-01-01 12:00:00 UTC | 251.454764° | 251.454735° | 0.11″ | 60″ | Pass |
| Pluto | 2024-01-01 12:00:00 UTC | 299.373176° | 299.372881° | 1.06″ | 60″ | Pass |
| Pluto | 2050-01-01 00:00:00 UTC | 337.533067° | 337.531776° | 4.65″ | 60″ | Pass |
| Chiron | 1950-01-01 00:00:00 UTC | 255.777288° | 255.798054° | 74.76″ | 1,800″ | Pass |
| Chiron | 2000-01-01 12:00:00 UTC | 251.617609° | 251.624558° | 25.02″ | 1,800″ | Pass |
| Chiron | 2024-01-01 12:00:00 UTC | 15.464911° | 15.464574° | 1.21″ | 1,800″ | Pass |
| Chiron | 2050-01-01 00:00:00 UTC | 246.587601° | 246.580693° | 24.87″ | 1,800″ | Pass |
48 raw cusp rows
House cusps
The compact table groups twelve published cusp rows per case. All individual values remain in the raw JSON.
| Case | UTC instant | Lat, lon | System | Cusps | Max error | Result |
|---|---|---|---|---|---|---|
| london-j2000 | 2000-01-01 00:00:00 UTC | 51.5074, -0.1278 | Placidus | 12 | 11.80″ | Pass |
| new-york-eclipse | 2024-04-08 18:00:00 UTC | 40.7128, -74.0060 | Placidus | 12 | 5.73″ | Pass |
| sydney-historical | 1950-01-01 00:00:00 UTC | -33.8688, 151.2093 | Placidus | 12 | 2.41″ | Pass |
| tromso-polar | 2024-06-21 12:00:00 UTC | 69.6492, 18.9553 | Placidus → Porphyry | 12 | 2.54″ | Pass |
6 timing rows
Transit crossings and stations
Crossings use a 90-minute floor. Stations use six hours because longitude is nearly flat around a station.
| Case | Event | JPL-derived UTC | PathFinder UTC | Error | Floor | Result |
|---|---|---|---|---|---|---|
| mercury-20-aries-direct-before-retrograde | 20° Aries crossing | 2024-03-21 23:56:28.778947 UTC | 2024-03-21 23:56:07.96875 UTC | 0.35 min | 90 min | Pass |
| mercury-20-aries-retrograde | 20° Aries crossing | 2024-04-15 08:58:34.841376 UTC | 2024-04-15 08:56:29.0625 UTC | 2.10 min | 90 min | Pass |
| mercury-20-aries-direct-after-retrograde | 20° Aries crossing | 2024-05-05 18:38:26.863024 UTC | 2024-05-05 18:37:58.125 UTC | 0.48 min | 90 min | Pass |
| mercury-april-direct-station | Station | 2024-04-25 12:54:01.463415 UTC | 2024-04-25 12:51:45.916906191 UTC | 2.26 min | 360 min | Pass |
| saturn-june-retrograde-station | Station | 2024-06-29 19:10:00 UTC | 2024-06-29 19:06:54.17098049 UTC | 3.10 min | 360 min | Pass |
| pluto-may-retrograde-station | Station | 2024-05-02 17:05:00 UTC | 2024-05-02 17:30:15.478278664 UTC | 25.26 min | 360 min | Pass |
3 civil-time rows
Historical IANA time zones
Resolved with TZDB: 2026c (mapping: 48.2). The Samoa gap is shifted forward under the documented product policy.
| Case | Requested local | Zone | Offset | Resolved UTC | Warning | Result |
|---|---|---|---|---|---|---|
| samoa-date-line-skip | 2011-12-30T12:00:00 | Pacific/Apia | +14 | 2011-12-30 22:00:00 UTC | dst_gap_adjusted | Pass |
| british-double-summer-time | 1941-07-01T12:00:00 | Europe/London | +02 | 1941-07-01 10:00:00 UTC | None | Pass |
| amsterdam-local-mean-time | 1850-01-01T12:00:00 | Europe/Amsterdam | +00:17:30 | 1850-01-01 11:42:30 UTC | None | Pass |
Required disclosures
What the headline leaves out
- Lunar node
- Mean node. The South Node is exactly opposite. Neither node is included in the JPL body rows.
- Black Moon Lilith
- Mean lunar apogee, not true or osculating Lilith. Excluded from JPL body rows.
- Chiron
- Gravity-simulated from a J2000 state vector and judged at a 0.5° floor; it is not an Astronomy Engine body.
- Angles and houses
- Public contract ±1°. Placidus is default; documented polar cases fall back to Porphyry.
- Aspects
- Custom per-aspect orb table with a 2° Sun/Moon bonus. Orb policy does not affect raw position rows.
- Claims boundary
- This benchmark tests calculation output only. It is not evidence that astrology predicts events, describes personality, or that an AI-written interpretation is accurate.