How Auspio Calculates Your Dates

1. Short answer

Auspio calculates auspicious dates by combining astronomical solar-term and lunar calendar boundaries with Ba Zi, the Twelve Day Officers (建除十二神), zodiac branch relationships, Five Elements (五行), and the event type you choose. It reports what those traditional systems say about a date; it does not promise that a chosen date will cause a particular outcome.

2. Astronomy layer

Auspio's solar terms are computed from the Sun's apparent geocentric ecliptic longitude, not from a hand-entered date list. The app's astronomy utility implements formulas from Jean Meeus, Astronomical Algorithms, 2nd edition: low-accuracy solar position for solar-term instants and the lunation series for new moons. Both are computed in Terrestrial Time and corrected back to UTC with a polynomial ΔT estimate.

The solar-term service computes all 24 节气 (solar terms) for a calendar year on first use, caches them by year, and stores each term as the UTC instant when the Sun reaches a target apparent longitude. The 24 terms are 15 degrees apart, from 小寒 (Xiao Han) at 285 degrees through 冬至 (Dong Zhi) at 270 degrees.

For ordinary calendar display, Auspio checks whether a solar-term instant falls on the same UTC+8 civil day. For Ba Zi calculations, it uses instant-based comparison instead, because a person born before or after a solar-term boundary can belong to a different month pillar.

3. Ba Zi pillars

Ba Zi (八字, Four Pillars) in Auspio is built from the year, month, day, and hour pillars. The year pillar changes at 立春 (Li Chun, Start of Spring), not on January 1 and not automatically on Chinese New Year. The app finds the most recent Li Chun at or before the birth instant, then uses that as the Ba Zi year boundary.

The month pillar changes only at the 12 primary terms, or 节 (jie), not at every solar term and not at the lunar month boundary. 立春 (Li Chun) begins the 寅 month, 惊蛰 (Jing Zhe) begins the 卯 month, and each following primary term advances the month branch. The month stem then follows the 五虎遁 (Five Tigers) rule.

The day pillar follows a continuous 60-day sexagenary cycle anchored in the app's implementation at 2000-01-01 = 戊午. The hour pillar follows the double-hour branches, with 子 hour covering 23:00 to 01:00, and the hour stem follows the 五鼠遁 (Five Rats) rule. The app currently uses the early-子 convention for the hour stem, while late 子 hour adjusts the day pillar for 23:00 to 23:59.

4. Date scoring

For a date search, Auspio scores each candidate day with four layers: the activity-specific Twelve Day Officer rating, zodiac branch compatibility against the participants' year animals, Five Elements harmony between the day stem and each participant's Day Master, and lunar-month cautions. In the current scoring engine, those layers are weighted as 40 percent Day Officer, 30 percent zodiac compatibility, 20 percent element harmony, and 10 percent lunar month.

The Twelve Day Officer is derived from the day branch's offset from the jie-based month branch. When the day branch equals the month branch, the day is 建 (Establish); the sequence then proceeds through 除, 满, 平, 定, 执, 破, 危, 成, 收, 开, and 闭. The event type matters: a day can be strong for moving, weaker for a wedding, and neutral for a general purpose.

The recommended hours use the day branch against each double-hour branch. Hours are marked favorable when the branch relationship is harmonious and are not presented as favorable when the relationship clashes.

5. Contested points

Some parts of Chinese metaphysics are not settled by one universal authority. Auspio documents those points instead of pretending they do not exist.

The first documented dispute is 置闰法 versus 拆补法 in 奇门遁甲 (Qi Men Dun Jia). Auspio's working QMDJ notes chose 置闰法 for the chart-casting method because multiple practitioner sources in the research notes treated it as the classical default, while acknowledging that 拆补法 and other methods exist. QMDJ is not currently shipped in the app; that work was reverted pending further research, with the tested work preserved separately.

The second documented dispute is the Yin-Dun Eight Gods naming issue. In the QMDJ investigation, the team expected one deity name in a Yin-Dun chart but found that the checked reference engine and written source notes disagreed on whether 白虎/玄武 or 勾陈/朱雀 should appear. The running reference output did not produce 勾陈/朱雀, so the tested QMDJ branch kept the reference-output reading and documented the naming dispute explicitly. Because QMDJ is not shipped, this is a research record rather than a current app feature claim.

6. What this page does not claim

This page does not say that Auspio is the only app that computes solar terms, true time, or Ba Zi boundaries. No recorded competitor test is on file, so Auspio does not claim that any named competitor is inaccurate.

It also does not claim a named school, lineage, or master as the source of the shipped calculation choices. Where the source files show an algorithm, this page names the algorithm. Where the research notes show disagreement, this page names the disagreement. Where something is not verified, it is left out.

Auspio is for entertainment, cultural reflection, and personal planning. For the legal wording, see the Terms of Service on professional advice and outcomes.

7. Source notes

The technical statements on this page are grounded in Auspio's current app source and internal verification notes as of July 31, 2026: the astronomy utility, the solar terms service, the Ba Zi service, the Twelve Day Officers service, the auspiciousness scoring service, the QMDJ/Ba Zi enhancement notes, and the algorithm verification report.