Midpoint Factory #

The MidpointFactory computes the midpoint of every unordered pair of active points in a chart. Midpoints are central to cosmobiology (Ebertin) and Uranian/Hamburg-school astrology, where they are treated as sensitive axes: when a third point crosses one, the energies of the defining pair are activated.

What It Computes #

The midpoint of every pair of active points (shorter arc convention)
The 90-degree modulus position for cosmobiology dial work
Optional aspect activations: which third points form aspects with each midpoint

Basic Usage #

from kerykeion import AstrologicalSubjectFactory, MidpointFactory

subject = AstrologicalSubjectFactory.from_birth_data(
    "John", 1990, 6, 15, 14, 30,
    lng=12.5, lat=41.9, tz_str="Europe/Rome", online=False,
)

midpoints = MidpointFactory.compute(subject)

for m in midpoints:
    print(f"{m.point_a}/{m.point_b}: {m.midpoint_position:.2f} {m.midpoint_sign}"
          f" (90 dial: {m.midpoint_modulus_90:.2f})")
    for a in m.aspects_to_midpoint:
        print(f"   activated by {a.point_name} ({a.aspect}, orb {a.orb:.2f})")

Methods #

`compute(subject, *, active_points, compute_aspects, aspect_orb, aspects)` #

Compute every pairwise midpoint and (optionally) aspect activations.

Parameter	Type	Default	Description
`subject`	AstrologicalSubjectModel	–	The natal/event chart to analyse
`active_points`	Sequence[str] or None	None	Points to use as midpoint constituents. Defaults to `DEFAULT_PREDICTIVE_POINTS`: Sun through Pluto, True North Lunar Node, Chiron, Ascendant and Medium Coeli. Names the subject does not carry are skipped, and fewer than two resolved points give an empty list
`compute_aspects`	bool	True	Also compute third-point aspect activations
`aspect_orb`	float	1.0	Orb in degrees for aspect-to-midpoint detection
`aspects`	Sequence[str] or None	None	Whitelist of aspect names (defaults to all configured)

Returns: List[MidpointModel]

`compute_active_midpoint_points(subject, pair_names)` #

Materialize midpoints as KerykeionPointModel entries so the chart drawer can render them like ordinary active points.

Parameter	Type	Description
`subject`	AstrologicalSubjectModel	The natal subject
`pair_names`	Sequence[str]	Pair identifiers in `"A_B"` form (e.g. `"Sun_Moon"`)

Returns: List[KerykeionPointModel], one per resolved pair, named "A_B_Midpoint" with point_type="Midpoint" and sign, element, quality and house derived from the midpoint longitude on the shorter arc. Both sides of a pair must resolve in the subject’s own active_points: a pair that does not is skipped and logged as a warning. A repeated pair, or the reversed "B_A" twin of one already emitted, is skipped too — the first occurrence wins.

Data Models #

`MidpointModel` #

Field	Type	Description
`point_a`	str	Name of the first point
`point_b`	str	Name of the second point
`point_a_abs_pos`	float	Absolute longitude of point A (0-360)
`point_b_abs_pos`	float	Absolute longitude of point B (0-360)
`midpoint_abs_pos`	float	Midpoint longitude on the shorter arc (0-360)
`midpoint_sign`	str	Three-letter zodiac sign code (Ari, Tau, …)
`midpoint_position`	float	Position within the sign in degrees (0-30)
`midpoint_modulus_90`	float	90-degree dial position (longitude % 90)
`aspects_to_midpoint`	List[MidpointAspectModel]	Third points that aspect this midpoint

`MidpointAspectModel` #

Field	Type	Description
`point_name`	str	Name of the third point that aspects the midpoint
`point_abs_pos`	float	Absolute zodiacal longitude of the third point
`aspect`	str	Aspect name (conjunction, trine, square, …)
`aspect_degrees`	int	Exact aspect angle in degrees
`orb`	float	Orb (deviation from exact aspect) in degrees

90-Degree Dial #

The midpoint_modulus_90 field converts the midpoint longitude to the 90-degree dial used in cosmobiology. This reduces the full 360-degree circle to a 90-degree range, making it easier to spot hard aspects (conjunction, square, opposition) as conjunctions on the dial.