For astrologers
What is under it
If you already read charts, the questions are different. Which zodiac, whose houses, what orbs, and where the numbers come from. All of it is here, and none of it is buried behind a subscription.
Eight traditions, side by side
Not a switch that relabels the same chart. Each mode carries its own zodiac, house system and vocabulary, and you can hold several open at once to see where they disagree.
| Mode | Zodiac | Houses | Aspects |
|---|---|---|---|
| Western tropical | Tropical | Placidus | Majors and minors |
| Western sidereal | Fagan-Bradley | Placidus | Majors and minors |
| Vedic | Lahiri | Whole sign | Majors, plus graha-drishti |
| Hellenistic | Tropical | Whole sign | Five majors only |
| Babylonian | Sidereal | None computed | Five majors only |
| Chinese BaZi | Four pillars on local civil time. Calendar family, no wheel. | ||
| Mayan Tzolk'in | GMT 584283 correlation. Calendar family, no wheel. | ||
| Egyptian decans | Anchored on the heliacal rise of Sirius. Calendar family, no wheel. | ||
Defaults, not limits. Ten house systems are available on any wheel mode — Placidus, whole sign, equal, Koch, Porphyry, Regiomontanus, Campanus, topocentric, Alcabitius and Morinus — and the ayanamsa is yours to set.
Vedic drishti are computed house-wise and returned alongside the degree-based aspects rather than instead of them, so a Vedic chart can show both without either being forced into the other's model.
Orbs you can set
Three named sets, or your own numbers per aspect. The default is Astrodienst-equivalent.
| Aspect | Tight | Standard | Loose |
|---|---|---|---|
| Conjunction ☌ | 5° | 10° | 12° |
| Opposition ☍ | 5° | 10° | 12° |
| Trine △ | 4° | 8° | 10° |
| Square □ | 4° | 8° | 10° |
| Sextile ✶ | 3° | 6° | 8° |
| Quincunx ⚻ | 1.5° | 3° | 4° |
| Minor aspects | 1° | 2° | 3° |
| Luminary bonus | +1° | +2° | +3° |
The luminary bonus is additive, and applies to conjunctions and oppositions involving the Sun or Moon. Semisextile, semisquare, sesquiquadrate, quintile and biquintile keep their own reading rather than being folded into hard and soft, because a quincunx is not a mild square.
Bodies and points
The ten planets and the lunar node are on by default. Beyond them, switch on what you work with: Lilith by either computation, Chiron and the centaurs, the four main asteroids, Eris and Sedna. Node and Lilith each offer mean or true, since those are one point computed two ways rather than two points.
Angles, cusps, dignities, sect, retrograde stations, returns and antiscia are computed rather than approximated. So are the sensitive points and the Arabic lots, on request.
Where the numbers come from
Positions are computed with Skyfield against JPL's DE440 ephemeris, with delta-T interpolated from a table matched to that kernel's tidal acceleration. Everything is regression-tested against Swiss Ephemeris, which is the reference the professional field uses.
| Quantity | Held to, against Swiss Ephemeris |
|---|---|
| Planetary longitude | 0.5″ |
| Lunar longitude | 2″ |
| Retrograde station times | 30 s (60 s for Jupiter and Saturn) |
| Eclipse maximum | 5 s |
| Solar eclipse type | exact, 2025–2035, hybrids included |
These are the bounds the test suite enforces on every build, across 1550–2400, so a chart for 1623 is held to the same standard as one for next week. Typical agreement is a good deal tighter than the bound. The full method, including what is deliberately left uncorrected and why, is on the methodology page.
What is not finished
Western tropical is the mode with the deepest editorial coverage: every placement, house, angle, cusp, dignity and aspect pair has authored text behind it. Vedic, Babylonian and the three calendar traditions carry placements but are marked review-pending in the app, because their dignity tables and vocabulary have not yet been through a specialist reader.
The app says so on the screen rather than here only. If you read in one of those traditions and the text is wrong, that is worth telling us, and it is the sort of thing that gets fixed.
If you read for other people
Fifty charts
The Unlimited tier holds fifty active charts and archives the rest without deleting anything. Comparisons between any two of them.
A calendar feed
Subscribe a client's transits into Apple Calendar, Google Calendar or anything that reads ICS. Two years of horizon, refreshed as it moves.
Nothing scored
No colour coding, no severity, no "good day" badges. Whatever verdict a chart gets in your consulting room is yours to give, not the software's.