Antiscia
Antiscia are points mirrored across the solstice axis, so two degrees that share the same day length are linked even when they form no ordinary aspect.
The mirror runs through 0 Cancer and 0 Capricorn. A planet at 10 Taurus has its antiscion at 20 Leo, because both stand the same distance from the longest day. The contra-antiscion is the mirror across the equinox axis instead.
It is a hidden connection: two planets can be linked by antiscia while looking unrelated on the aspect grid, which is exactly why traditional astrologers check for it.
Frequently asked
Is an antiscion as strong as an aspect?
Traditional sources treat it as a real but quieter connection, usually with a tight orb of a degree or so.
What is a contra-antiscion?
The same mirroring taken across the equinox axis rather than the solstice axis, and read as the more tense of the two.