PracticeEco method library
Birth time in a Purple Star chart
Why two-hour periods matter, how a remembered range is handled, and why unknown time is not replaced with noon.
What the implementation can support
In this implementation, birth time selects one of twelve two-hour branches and directly affects the Life palace. Month and hour locate that reference point; the twelve palace names, element bureau, and star positions build from it. A guessed time can therefore produce a precise-looking chart for the wrong branch, which is why PracticeEco does not quietly substitute noon.
The form asks whether you know your birth time: Yes, Roughly, or No. An exact time is checked against the recorded time zone; if that local time occurred twice, you choose the occurrence from your birth record. A remembered same-day range is checked minute by minute, duplicate charts are collapsed, and each distinct candidate is shown with its clock-time ranges. If you choose No, the form uses your whole birth date, from 00:00 to 24:00, and shows the distinct candidate charts with their clock-time ranges. The number depends on the date and birthplace. You choose which candidate to look at; the tool does not pick a birth time for you. A range that crosses midnight must be entered as two runs because the date changes too.
Longitude and historical time-zone offset also matter to the local-solar-time calculation. They are used in the browser for the free result and are not a reason to ask for an email. The practical next step is to widen a range only as far as memory supports, compare the candidates structurally, and look for a birth record or family recollection instead of treating recognition as verification.
Use and limits
This page explains a rule, label, or product boundary. It is not a clinical instrument, a forecast, or a substitute for direct evidence about a person. Different Purple Star astrology schools can use different calendar and transformation choices.
Sources and reproducibility
- Hong Kong Observatory: Gregorian–Lunar Calendar Conversion Table — The calendar-conversion layer used before the chart rules run.
- iztro: open-source Zi Wei Dou Shu implementation — A named, reproducible reference implementation for chart placement.
- iztro documentation: palace and star data structures — The distinction between palaces, major stars, and an opposite palace.
- Standards for Educational and Psychological Testing — The boundary between a reflection exercise and a validated interpretation or use.