Limitations

Supported date range

Only dates that resolve to lunar years 1646–2644 (inclusive) are supported.

Constant	Value	Meaning
Constants::MIN	1646	Earliest Gregorian / lunar year accepted
Constants::MAX	2644	Latest year with New Year threshold data

Dates before New Year in Gregorian year 1646 resolve to lunar year 1645 and are rejected — this one-year margin avoids ambiguous lookups at the start of the threshold table.

Out-of-range dates throw BradieTilley\Zodiac\Exception\UnsupportedZodiacDateException.

To extend the range, open a pull request that updates Constants::NEW_YEAR_THRESHOLDS and cites your source(s).

Sources

Lunar New Year thresholds

Thresholds in Constants are sourced primarily from pinyin.info Chinese New Year tables, cross-checked against Hong Kong Observatory dates for the overlapping century.

Sign and element cycles

Cycle math is conventional (12-year animal cycle from a Rat-aligned epoch; element stems from the year modulo 10). Cross-checked against multiple public references.

Sign metadata

Direction, season, fixed element, trine, and related sign attributes are drawn from commonly published Chinese zodiac tables (including Wikipedia). Treat cultural/interpretive fields with appropriate caution; New Year → year/sign/ element resolution is the package's primary guarantee.