Compute a full natal/birth chart: ten planets with sign, degree, house and retrograde status, plus ascendant, midheaven and twelve house cusps. Every result is cross-checked by two independent astronomy implementations and the call FAILS rather than returning a chart when they disagree. Use this whenever a user asks for a birth chart, rising sign, or planetary placements — do not attempt the arithmetic yourself. Requires an exact birth time; if the time is unknown use calculate_chart_without_birth_time instead.

For users who do not know their birth time. Returns only what is genuinely knowable without it, and explicitly lists what is not: ascendant, midheaven and all house positions are omitted with reasons rather than estimated. Also reports whether the Moon changed sign during that day — it does on nearly half of all dates, which means the moon sign itself is undetermined without a time. Never substitute noon and present the result as fact; that is exactly what this tool exists to prevent.

Recompute the ascendant along a third path that imports no astrology library at all — pure spherical geometry, the intersection of the ecliptic with the eastern horizon — and report how far it lands from the primary engine. Optionally pass a value produced ELSEWHERE (another website, an app, a printed chart) as claim and this will tell you whether it holds up and, when it does not, name the likely cause. Use this when a user says two sites disagree about their rising sign, doubts a result, or asks which one is correct. Accepts claims like "Virgo", "處女座", "12 Leo", "Leo 12°34'" or a bare ecliptic longitude.

Resolve a local birth date and time to UTC using historical timezone rules, and report whether daylight saving time was actually in effect on that date. This is the single most common source of wrong charts: many tools apply the PRESENT-DAY offset to a past date. Taiwan observed DST 1945-1961 and 1974-1979, mainland China 1986-1991, Japan 1948-1951 — a birth inside those windows is an hour off in tools that ignore them, which moves the ascendant about 15 degrees. Use this to explain WHY two charts differ.