True Solar Time in BaZi: Why and How to Correct Birth Time
True Solar Time Basics
Clock Time vs. Solar Reality
True solar time uses the Sun's actual position, while standard clock time assumes uniform motion. Correction usually includes longitude adjustment (about 4 minutes per degree from the standard meridian) and the equation of time. In China, standard time is based on 120°E, so longitude differences are added or subtracted before applying the equation of time. The correction is most important when a birth time is near a day or hour boundary.
Where It Changes Readings
Career & Wealth
Small time shifts can change the hour pillar, which may alter timing cues for career or wealth phases.
Love & Relationship
Relationship indicators tied to hour or day can change when the birth time is near midnight.
Personality
Personality structure remains, but expression timing may shift when corrections change the hour pillar.
Use accurate time to reduce interpretation noise when health themes depend on the hour pillar.
Notes on Time Correction
How to Calculate True Solar Time
Collect Longitude: Get the birth location longitude to compute the correction to the standard meridian.
Apply Equation of Time: Add or subtract the equation of time after longitude correction to get true solar time.
Re-check Boundaries: If the corrected time crosses midnight or a two-hour boundary, update the day or hour pillar.
True Solar Time FAQs
It is most relevant for professional-grade readings and for births close to day or hour boundaries.
It can, but only if the correction crosses midnight.
No. The equation of time also matters because the Sun's apparent motion is not uniform.