Inputs
A natal chart needs the local birth date, local clock time, and birthplace. AskCelesta resolves the selected place to latitude, longitude, and timezone, then converts the local moment into the time basis used by the ephemeris calculation.
Planetary positions
The backend uses the Kerykeion astrology calculation library and its astronomical ephemeris support to calculate ecliptic longitudes. A position is displayed as a zodiac sign plus an exact degree within that sign. Retrograde status is calculated from planetary motion rather than generated by an AI model.
Angles and houses
The Ascendant, Midheaven, and house cusps depend strongly on time and location. A small time error changes their degrees and, near a boundary, may change a sign or house placement. If a birth time is unknown, planetary signs may still be useful, but the Rising sign and houses should not be treated as reliable.
Aspects and orbs
AskCelesta compares absolute zodiac longitudes and measures angular separation. It displays conjunctions, sextiles, squares, trines, oppositions, and supported minor aspects when the separation falls within the selected orb. The exact orb is shown so users can evaluate closeness rather than relying only on an aspect label.
Synastry
Synastry compares positions from two separately calculated natal charts. Direction matters: the first person's planet is interpreted in relation to the second person's planet. One contact never determines an entire relationship; signs, houses, aspect patterns, and both complete charts provide context.
Today's sky
The daily collective view uses a stable 12:00 UTC Greenwich reference for each UTC date. Planetary signs are broadly shared, while angles and houses are specific to that reference time and place and are labeled accordingly.
Limitations and corrections
Results depend on the accuracy of supplied birth data, timezone handling, supported ephemeris range, and chosen settings. For historical dates outside the supported Chiron range, the public catalog may omit Chiron while retaining supported classical positions. Report reproducible calculation questions to askcelesta@gmail.com with the input data, expected result, comparison source, and settings used.