V12 current — H(r) exponential curve — mean error 5.2%, median 4.4%
Key V50.6 discovery: H is not constant. The firmament curves downward from pole toward rim.
H(r) = 8537 × exp(−r / 8619) km r(city) = solve numerically: r × tan(polaris_elevation) = H(r) θ = Δlon × 0.9941 (EW angular scale) distance = sqrt(r1² + r2² − 2 × r1 × r2 × cos(Δθ)) where Δθ = Δlon × 0.9941
Performance: mean 5.2%, median 4.4% across 19 city pairs (was ~40% in V9).
V9 used flat H=4,750 km and solar noon UTC as theta proxy. V50.6 replaced both with H(r) exponential and Δlon × 0.9941.
Input: Solar noon altitude at June solstice + solar noon UTC Output: r, θ lat_S = 90 − noon_altitude_june + 23.44 (June dec = −23.44°) r = H / tan(lat_S) θ = (solar_noon_utc − 12.0) × 15°
d = sqrt(r1² + r2² − 2 × r1 × r2 × cos(Δθ)) Correct for polar disc geometry. Arc formula d = r_avg × Δθ used in V1–V8 is only valid for very small Δθ. Replaced at V9.
r_ellipse(θ) = (a × b) / sqrt((b × cos(θ − orient))² + (a × sin(θ − orient))²) a ≈ 20,015 km (semi-major, pole to equatorial boundary) b ≈ 15,000 km (semi-minor, refining) b/a = 0.70–0.90 (V5–V9 range, converging) orient ≈ 60° (NE from Greenwich, Atlantic-to-Asia axis)
Ellipse-over-circle: LOCKED. Ellipse outperforms circle across all versions (WIN-030). Parameters: not yet locked — WGS84 contamination in source coordinates (OPEN-001). V10 will use sunrise/sunset times only.
| Issue | V9 Error | V12 Status | Fix |
|---|---|---|---|
| Oslo-Stockholm | −89% | 0.0% — RESOLVED | V12 H(r) + correct θ from longitude |
| Southern over-prediction | Quadratic with latitude | Reduced (V12 EW scale) | Further refinement with dome-native coords |
| Cross-equator | 25–78% on long pairs | Under revision | V12 H(r) + ellipse |
| City | Polaris ° | Noon UTC | r (km) | θ ° | x (km) | y (km) |
|---|---|---|---|---|---|---|
| North Pole | 89.99 | 0.00 | 1 | −180.0 | −1 | 0 |
| Reykjavik | 64.10 | 13.93 | 2,306 | +28.9 | 2,018 | 1,116 |
| Anchorage | 61.20 | 22.80 | 2,611 | +162.0 | −2,484 | 807 |
| Oslo | 59.90 | 12.23 | 2,753 | +3.5 | 2,748 | 166 |
| Stockholm | 59.33 | 12.07 | 2,817 | +1.1 | 2,817 | 54 |
| Moscow | 55.75 | 9.57 | 3,234 | −36.4 | 2,601 | −1,921 |
| London | 51.50 | 12.00 | 3,778 | +0.0 | 3,778 | 0 |
| Warsaw | 52.20 | 10.60 | 3,684 | −21.0 | 3,440 | −1,320 |
| Berlin | 52.50 | 11.07 | 3,645 | −13.9 | 3,537 | −879 |
| Paris | 48.90 | 11.85 | 4,144 | −2.3 | 4,140 | −163 |
| Chicago | 41.88 | 17.80 | 5,298 | +87.0 | 277 | 5,290 |
| Istanbul | 41.01 | 9.47 | 5,462 | −37.9 | 4,307 | −3,359 |
| Madrid | 40.42 | 12.47 | 5,577 | +7.1 | 5,535 | 685 |
| New York | 40.71 | 16.87 | 5,520 | +73.1 | 1,609 | 5,281 |
| Denver | 39.73 | 19.13 | 5,715 | +106.9 | −1,666 | 5,467 |
| Chapel Hill NC | 36.18 | 17.25 | 6,495 | +78.8 | 1,267 | 6,370 |
| Tokyo | 35.70 | 2.73 | 6,610 | −139.0 | −4,993 | −4,332 |
| Los Angeles | 34.05 | 19.87 | 7,029 | +118.1 | −3,305 | 6,203 |
| Cairo | 30.10 | 9.87 | 8,194 | −32.0 | 6,953 | −4,336 |
| Baghdad | 33.30 | 8.47 | 7,231 | −52.9 | 4,357 | −5,771 |
| Miami | 25.80 | 17.27 | 9,826 | +79.0 | 1,866 | 9,647 |
| Mexico City | 19.43 | 18.60 | 13,466 | +99.0 | −2,107 | 13,300 |
| Mumbai | 19.08 | 6.20 | 13,733 | −87.0 | 719 | −13,714 |
| Hong Kong | 22.32 | 3.80 | 11,570 | −123.0 | −6,302 | −9,704 |
| City | Noon Alt (June) | Noon UTC | lat_S ° | r (km) | θ ° | x (km) | y (km) |
|---|---|---|---|---|---|---|---|
| Sydney | 33.0° | 14.17 | 33.6°S | 7,160 | +32.5 | 6,035 | 3,852 |
| Cape Town | 33.6° | 10.00 | 33.0°S | 7,326 | −30.0 | 6,344 | −3,663 |
| Buenos Aires | 33.5° | 15.87 | 33.1°S | 7,298 | +58.0 | 3,862 | 6,192 |
| Santiago | 37.0° | 16.87 | 29.6°S | 8,375 | +73.1 | 2,442 | 8,011 |
| Melbourne | 30.0° | 14.40 | 36.6°S | 6,405 | +36.0 | 5,182 | 3,765 |
| Auckland | 23.5° | 14.27 | 43.1°S | 5,083 | +34.0 | 4,212 | 2,846 |
| Johannesburg | 42.0° | 9.73 | 24.6°S | 10,394 | −34.0 | 8,612 | −5,820 |
| Perth | 38.0° | 12.13 | 28.6°S | 8,727 | +2.0 | 8,722 | 297 |