ephemengine.com

A person's birth chart.

The sky at a moment and place — not tied to any person.

Where the visible bodies land in a framed photo of the sky, for an image prompt.

A time sequence of sky frames for an animation: the same place, aim, and lens stepped through time.

Check an authored synthetic celestial system for ill-defined inputs: duplicate body ids, non-positive periods, out-of-range eccentricity, or a dangling observer.

Positions of every body in an authored synthetic system at one instant.

Sky View for a mix of real and synthetic bodies: register the authored system on an ephemeral engine, then frame the visible sky like sky_view.

Transiting planets vs natal chart: aspects within orb (applying/separating), natal house per transiting body.

Compare two people's birth charts: inter-chart aspects with orbs, house overlays both ways, plus ranked citable fact atoms and a ready `brief` (synastry/composite ids for auditCitations).

Exact dates a transiting body makes an aspect, within a range: to a fixed longitude OR to another transiting body.

Rectification sweep: ASC/MC at each step across a window of UTC hours on one date, with ASC sign-change times.

Sky events in a UTC date range: rise/set/meridian transits (need lat+lon+body), lunar phases (new/quarters/full), solar and lunar eclipses, stations (body turns retrograde/direct; needs body), zodiac degree crossings (needs body + target_lon).

Planetary hours for a moment and place: the unequal hour in effect (its ruler, day/night, hour number 1-24, start/end UTC), the ruler of the planetary day, and the full 24-hour ruler sequence.

Void-of-course Moon at a moment: whether the Moon makes no further Ptolemaic aspect to a traditional planet (Sun..Saturn) before it leaves its current sign.

Solar or lunar return: the instant(s) a body returns to its natal longitude within a window, plus the full return chart for the first one.

Secondary progressions (day-for-a-year) and solar-arc directions of a natal chart to a target date.

Relationship charts for two people: the midpoint composite (each body and angle is the shorter-arc midpoint of the two natal positions) and the Davison chart (a real chart cast for the midpoint in time and place).

Essential dignity and sect for the seven traditional planets at a moment and place.

The seven Hermetic lots (Arabic parts) — Fortune, Spirit, Eros, Necessity, Courage, Victory, Nemesis — cast from the Ascendant and reversing direction by sect (a chart is day when the Sun is above the horizon).

Annual and monthly profections (a Hellenistic time-lord technique) at a target date.

Firdaria (firdariyyat): the Persian/medieval planetary time-lord periods.

Zodiacal releasing (aphesis), the Hellenistic time-lord technique from Vettius Valens, released from a Lot (Spirit by default, or Fortune).

Primary (mundane) directions of the seven traditional planets to the four angles (MC, IC, Ascendant, Descendant), and optionally between the planets themselves.

The nakshatra (one of the 27 lunar mansions of 13°20′) of each classical point on the sidereal zodiac: the seven traditional planets and the Ascendant (lagna).

Vedic dasha periods — planetary time-lord cycles started from the Moon's birth nakshatra.

Parashari divisional charts (vargas): the sign of each of the seven planets and the Ascendant in the requested D-charts — D1 rasi, D2 hora, D3 drekkana, D9 navamsa, D10 dasamsa, D12 dwadasamsa, D30 trimsamsa.

Vedic yogas (planetary combinations) on the sidereal rasi chart: the five Pancha Mahapurusha yogas (Ruchaka, Bhadra, Hamsa, Malavya, Shasha), Gajakesari, Budha-Aditya, and Chandra-Mangala; whether Kemadruma (the isolated-Moon yoga) is present; the raja yogas (a kendra lord associating with a trikona lord) and dhana (wealth) yogas, each as the lord pair and how they associate (conjunction, aspect, or exchange); and the chart's yogakarakas (a planet ruling both a kendra and a trikona).

Classical aspect configurations in a chart: T-squares, grand trines, grand crosses, yods, kites, mystic rectangles, and stelliums by sign and by house.

Parans (paranatellonta): co-angular bodies over the 24 hours from a date at a latitude — every pair of bodies simultaneously on one of the four angles (rising, culminating, setting, anti-culminating) within a stated tolerance.

A chart's structural signature as plain counts: element, modality, angularity, quadrant, and hemisphere distributions over the bodies; the dominant element, modality, and most-occupied sign; and the classical chart ruler (the ruler of the Ascendant's sign).

A chart's validated facts as ranked, citable atoms for interpretation.

A birth chart, perturbed — a 'what if'.

Find when the sky most resembled a reference moment.

Rank moments in a window for an electional aim.

The mundane sky on a date: the active aspect configurations among the transiting planets (T-squares, grand trines, grand crosses, yods, kites, mystic rectangles, stelliums by sign), any planet stationing within a window, and whether the Moon is void of course.