Formula · Astronomy and calendar
The gap between true and mean solar time, swinging within plus or minus 16 minutes over a year. That is wide enough to move an hour pillar: two births fifteen minutes apart can land in different hours.
Standard approximation, error under 30 seconds
Astronomy and calendar
This one is astronomy and calendar: verifiable against civil dates and solar-term tables.
Related: Chart tool · all formulas · tools
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It is the same entry listed on the method page, used in pages such as Chart tool; the link above shows it in context.
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This one is astronomy and calendar: verifiable against civil dates and solar-term tables.