Davison chart calculator: the relationship as a real moment

That is what separates it from the composite, and the difference is worth understanding before you read either. A composite chart averages the two charts point by point — your Sun and theirs make a composite Sun. It is a useful abstraction, but no sky ever looked like it: it has no moment, so it cannot be progressed, transited or given a return. The Davison has a date, so all three work on it. The two charts disagree about a couple, and they are meant to: the composite is the relationship as an idea, the Davison is the relationship as an event in the world.

The midpoint in space is the average of the two latitudes and the two longitudes, as Ronald Davison drew it and as most astrology software does, so the houses here match a Davison cast elsewhere. One case is handled differently: when the two birthplaces lie either side of the 180th meridian, the longitudes are averaged the short way round, so Tokyo with Los Angeles meets in the Pacific between them rather than somewhere in Asia Minor.

Read it as a chart in its own right first. Its Sun says what the relationship is for, its Moon how it feels from inside, its Ascendant how it appears to everyone else, and the aspects between its planets describe the relationship's own tensions rather than either person's. Only then compare it with the two birth charts it came from.

Both birth times matter here, and for the same reason as in any chart: the planets are fine without them, the houses and angles are not. Two unknown times still give a readable Davison of planets and aspects, but its Ascendant and its house placements will be guesses, and those carry much of what the chart has to say about how a relationship is lived.

The place the midpoint lands is often nowhere either person has been — the middle of an ocean, a country neither has visited. That is expected and it does not weaken the chart. The midpoint is a construction, not a destination; what it does is fix the houses, and it fixes them consistently for the pair.

A relationship chart describes a relationship; it does not grade one. A Davison with hard aspects is not a verdict, and an easy one is not a guarantee — both describe what the pair will keep meeting, which is information two people can use rather than a score they have to accept.