Transit windows and natal or event-chart contacts
How transit-to-chart contacts remain coherent when each model uses its own frame, natal features, orb policy, and exact-hit chronology.
Frame comparison · released 2026-08-18
Shared fact substrate
Pure angular separation between two ecliptic longitudes is invariant when the same offset is applied to both; the underlying pair of bodies and motion remain the same.
Required shared inputs
- Frozen natal or event instant
- Transit search interval
- Ephemeris version
- Aspect and orb policy
- Frame-specific natal features
Tropical view
Transits are matched to tropical natal longitudes and tropical sign or house conditions under a tropical rule namespace.
Lahiri-sidereal view
Transits are matched to Lahiri-sidereal natal longitudes and Jyotiṣa sign, house, nakṣatra, or lordship conditions under a sidereal namespace.
Where they agree
Degree-based conjunctions and angular aspects can occur at the same instants when both endpoints are transformed consistently, subject to identical apparent-position choices.
Where they disagree
Sign labels, house applications, dispositors, nakṣatras, and eligible interpretation rules can disagree even when an exact angular contact is shared.
Preservation policy
Keep shared angular hits separate from frame-conditioned labels and rule matches; each narrative paragraph must cite the feature namespace it consumed.
Prohibited synthesis
Do not calculate the transit in one frame and compare it with a natal point from the other, or count one shared angular hit as independent confirmation by two systems.
What empirical comparison requires
Treat tropical and sidereal outputs as separate candidate models. Any performance claim requires preregistered features, outcomes, horizons, baselines, model-selection policy, multiplicity control, and prospective scoring that retains misses and abstentions.
Method sources
These sources define calculation and namespace policy. They do not determine which astrology system is true.
- Celestial timing reference library
Maha Celestial
Frame-explicit ingress, station, lunation, repeated-crossing, and Vimśottarī chronology conventions.
Boundary: A deterministic event date is not evidence that the event predicts a real-world outcome.
- Astrology tradition registry
Maha Celestial
Named, versioned rule namespaces and the separation between source provenance and empirical support.
Boundary: A well-sourced traditional rule remains an unvalidated interpretive claim unless separately tested.
- Tropical versus sidereal astrology
Maha Celestial
The policy that tropical and sidereal charts remain parallel declared models with separate feature and rule namespaces.
Boundary: The guide is a methodology declaration, not an adjudication between traditions.