Applying and separating aspects
The extra motion calculation needed to determine whether two bodies are moving toward or away from exact angular contact.
Calculation contract · released 2026-08-18
Definition
An aspect is applying when the selected signed phase is approaching its exact angle under the bodies’ relative apparent motion; it is separating after the crossing.
Calculation procedure
Evaluate signed aspect phase and relative longitudinal speed in a common frame, account for stations and wraparound, and verify the classification by solving for the nearest exact crossing.
Required inputs
- Both longitudes and apparent speeds
- Exact aspect angle
- Direction and wrap policy
- Search interval
Maha convention
Maha currently reports aspect type and orb but does not claim applying/separating status in production; this contract defines the required extension.
Uncertainty and edge cases
A station or near-zero relative speed can reverse the classification, and a finite daily difference can miss an intervening turn.
What this does not establish
Applying status does not by itself make an interpretation stronger or an event more likely.
Authoritative references
These sources establish the calculation vocabulary, data product, or transformation convention. They do not establish astrological interpretation.
- Horizons System Manual
NASA/JPL Solar System Dynamics · 4.98d (2025-11-21)
Solar-system object identifiers, observing centers, time inputs, reference frames, corrections, output quantities, and stated ephemeris limitations.
Boundary: Horizons output is authoritative only with the complete query contract preserved; transformed or rounded values require their own provenance record.
- Astronomy Engine
Don Cross (cosinekitty) · 2.1.19
Locally computed Sun and Moon positions derived from the VSOP87 and JPL-derived lunar theories, together with rise and set times, at the accuracy stated in the library documentation.
Boundary: Positions are computed in process rather than fetched from an authority, so a fact citing this source carries a digest over the computed values and not over a provider response body. Its accuracy is adequate for calendrical work and is not a substitute for a Horizons query where sub-arcsecond agreement matters.