Ptolemy / Semi-Arc Primary Directions Truth Card

Historical Name

• Ptolemy
• Ptolemy / semi-arc

Mathematical Basis

• semi-arc primary-direction family
• historically central to the mixed-ascension / semi-arc tradition
• on Moira's current admitted branch, the governing law is the proportional semi-arc and ascensional method family:
  • MC/IC directions by right ascension
  • ASC/DSC directions by oblique ascension / descension
  • non-angular points by the proportional semi-arc method:
  • PD = MD(significator) / SA(significator)
  • PP = SA(promissor) * PD
  • arc = PP - MD(promissor) if the promissor moves away from the meridian
  • arc = MD(promissor) - PP if the promissor moves toward the meridian

Interpretive Meaning

• perfection through a Ptolemaic semi-arc doctrine
• the branch now stands on its own governing semi-arc law rather than on a borrowed classic semi-arc implementation

Current Moira Admission

• admitted as a narrow explicit branch
• runtime-selectable on:
  • in_mundo
• active relation policy on the plain positional branch:
  • conjunction
  • opposition
• currently uses explicit sub-laws in the engine:
  • angular RA
  • angular OA/OD
  • non-angular proportional semi-arc
• current explicit derived-relation expansions:
  • zodiacal aspect branch via zodiacal_aspect
  • narrow declination-equivalence branch via parallel / contra-parallel

Boundary

• this does not claim that the full Ptolemaic family has been exhausted
• wider distinctions among historical semi-arc branches may emerge as Moira admits more target doctrine and aspect doctrine

Epistemic Status

• verified narrow admission

Mathematical Sovereignty

• sovereign on the current admitted branch
• wider Ptolemaic distinctions remain possible later, but the present branch is no longer mathematically borrowed