Composite chart

The other well-known way of giving a relationship its own chart: instead of one real moment, each planet is placed at the midpoint between the two people's positions of that planet. It is widely used, but the result is not a sky that ever existed, and those midpoints stop being clearly defined for more than two people. Aunt Starling uses a Davison chart instead, which is a real moment and so still works for a whole murmuration.