Secondary Progressions #

The SecondaryProgressionFactory computes secondary progressions – the most widely used predictive technique in Western astrology. Its symbolism is “a day for a year”: the chart calculated for the natal location N real days after birth represents the N-th year of the native’s life.

The Sun progresses ~1 degree per year, the Moon ~12 degrees per year. The factory also calculates progressed-to-natal aspects for predictive timing.

Basic Usage #

from kerykeion import AstrologicalSubjectFactory, SecondaryProgressionFactory

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

# Simple: get the progressed subject model
progressed = SecondaryProgressionFactory.compute(
    natal,
    target_iso_utc_datetime="2026-04-25T00:00:00Z",
)

print(f"Progressed Sun: {progressed.sun.sign} at {progressed.sun.position:.2f}")
print(f"Progressed Moon: {progressed.moon.sign} at {progressed.moon.position:.2f}")

Methods #

`compute(natal_subject, *, target_iso_utc_datetime, target_year, progressed_subject_name)` #

Returns a progressed AstrologicalSubjectModel that works transparently with all downstream tools (aspects, charts, reports).

Parameter	Type	Default	Description
`natal_subject`	AstrologicalSubjectModel	—	The natal chart
`target_iso_utc_datetime`	str or None	None	Target moment in ISO UTC format
`target_year`	int or None	None	Shorthand: progress to January 1 of this year
`progressed_subject_name`	str or None	None	Custom name for the progressed subject

Provide either target_iso_utc_datetime or target_year, not both.

`compute_full(natal_subject, *, ...)` #

Returns a SecondaryProgressionsResultModel with the progressed subject plus progressed-to-natal aspects.

Parameter	Type	Default	Description
`natal_subject`	AstrologicalSubjectModel	—	The natal chart
`target_iso_utc_datetime`	str or None	None	Target moment in ISO UTC format
`target_year`	int or None	None	Shorthand: progress to January 1 of this year
`progressed_subject_name`	str or None	None	Custom name for the progressed subject
`active_points`	Sequence[str] or None	None	Points to include in aspect calculations
`compute_aspects`	bool	True	Whether to compute progressed-to-natal aspects
`aspect_orb`	float	3.0	Orb in degrees for aspect detection
`aspects`	Sequence[str] or None	None	Whitelist of aspect names (defaults to the 5 Ptolemaic majors: conjunction, opposition, trine, square, sextile)
`point_orb_adjustments`	Mapping[str, float or Mapping[str, float]] or None	None	Finite additive per-point orb adjustments; entries may be aspect-keyed with a `"*"` default
`point_orb_adjustment_strategy`	str	“max_explicit”	`max_explicit`, `min_explicit`, `sum`, or `none`

result = SecondaryProgressionFactory.compute_full(
    natal,
    target_iso_utc_datetime="2026-04-25T00:00:00Z",
    aspect_orb=1.5,
)

print(f"Ephemeris date: {result.ephemeris_iso_utc_datetime}")

for asp in result.progressed_to_natal_aspects:
    print(f"P.{asp.progressed_point} {asp.aspect} N.{asp.natal_point} (orb: {asp.orb:.2f})")

Data Models #