Case 14 of 26
True-solar crossings
London: Equation of Time crosses an hour boundary
Near the February Equation-of-Time minimum, a small clock difference can change the hour branch.
Boundary question
Does Equation of Time participate even near the reference meridian?
Yes. The 01:10 record corrects to 00:55, crossing back into Zi Hour despite longitude being close to Greenwich.
Synthetic input
Recorded facts
- Date
- 1990-02-12
- Recorded time
- 01:10
- Location
- London, United Kingdom
- Time zone
- Europe/London
- Longitude
- -0.1276°
- Gender input
- Female
Pinned expected facts
Verified output
Year
庚午
Month
戊寅
Day
戊申
Hour
壬子
- Day Master
- 戊
- True solar time
- 1990-02-12 00:55
- Total correction
- -14.73 minutes
- Historical offset
- UTC+00:00 · DST 0 min
- Luck direction
- 逆排
- Reference Jie
- 立春 · 1990-02-04 10:14:00
- Luck start
- 1992-08-25 11:27:16
Conventions and limits
What this case does — and does not — prove
It verifies
Deterministic reproduction of this input under the named engine version and conventions. A pinned-field mismatch stops the production build.
It does not claim
Universal agreement across Bazi schools, interpretation of a real person, or certainty where the historical record is incomplete.
tyme4ts 1.5.2 · cantian-tymext 0.0.27 · sect 2 day boundary · BaziCalculator.ai NOAA/IANA true-solar adapter
calculation-benchmarks-v1 · reviewed 2026-09-05