What PairAstro is
A modern astrology tool built around three questions: who am I, how do I connect with this person, and where do I feel at home. Most astrology sites answer the first one. This one is built for the second and third as well — which is what the name is about.
How the charts are calculated
Planetary positions come from astronomy-engine, a modern implementation of the VSOP87 planetary theory and the ELP-2000 lunar theory. Positions are apparent, referred to the true ecliptic and equinox of date — the tropical zodiac used in Western astrology. Accuracy is well under an arc-minute across any date a birth chart needs, which is far finer than any interpretation depends on.
Local birth times are converted to UTC using the IANA time zone database through your browser, so historical daylight-saving rules are handled correctly rather than assumed.
The Life Map draws each planet's rising, setting, culminating and anti-culminating lines from the same positions, sampled across latitude. The coastline is Natural Earth 1:110m land (public domain), simplified and inlined so the map needs no external requests.
Houses use Placidus, the most common system in modern Western astrology, solved by semi-arc iteration. Placidus is mathematically undefined inside the polar circles; where that happens the chart falls back to whole-sign houses and says so on the page rather than quietly producing nonsense.
Where the interpretations come from
The readings are written against standard astrological tradition — sign elements and modalities, planetary rulerships, and the usual aspect set with conventional orbs. Compatibility scores are deterministic: the same two signs always produce the same numbers, derived from the relationship between the signs rather than from a table of opinions.
Everything is phrased as tendency and pattern. Nothing is phrased as prediction, because astrology does not support prediction and pretending otherwise is how this subject does harm.
What this site will not do
- Tell you whether to stay in or leave a relationship.
- Tell you what is going to happen.
- Offer medical, psychological, legal or financial guidance.
- Tell you that a difficult chart means a doomed relationship.
Your data
Every calculation runs in your browser. Birth details are never sent to a server. They are saved to your own device so you do not have to retype them, and they are included in the link if — and only if — you choose to share a result. Clearing your browser storage removes them.
Is any of this true?
There is no scientific evidence that planetary positions influence personality or events. We say soat length, on its own page, because a site that takes your birth time seriously should also be honest about what it is doing with it. Astrology works as a structured vocabulary for self-reflection. That is the claim, and it is the only one.