Born During Daylight Saving Time? Subtract One Hour First
Many regions ran daylight saving time (DST) in various periods — Hong Kong across multiple spans between 1941–1979, Taiwan 1945–1961 and 1974–1979, and most Western countries still do today. A clock time recorded during DST must be shifted back one hour before charting — skip this and the birth hour branch can land in the wrong two-hour block entirely.
How to handle it
- Birth certificate shows a DST period → subtract one hour
- If the corrected time lands near an hour-branch boundary (e.g. 10:55 vs 11:05), cast both candidate hours and compare
- Then apply true solar time correction: charts use the sun's actual position at the birthplace, not clock time. Longitude offset plus the equation of time can shift the reading by tens of minutes — combined with DST, hour-branch flips are common.
On Ming Luo Pan, enter the clock time as recorded (minus the DST hour); true solar time correction is built in.
The one-liner
DST is a clock humans pushed forward; true solar time is where the sun actually was. Charts need the latter — wind the artificial hour back first, then correct for astronomy.