Why does the Jyotiṣa layer use a sidereal frame?
The registered Jyotiṣa rule namespace declares a sidereal zodiac and the implementation names Lahiri where that specific convention is used. This is a tradition and calculation contract: it keeps frame-dependent features such as nakṣatra and Vimśottarī eligibility explicit. It is not a claim that every Jyotiṣa lineage uses one setting.
Direct answer
The registered Jyotiṣa rule namespace declares a sidereal zodiac and the implementation names Lahiri where that specific convention is used. This is a tradition and calculation contract: it keeps frame-dependent features such as nakṣatra and Vimśottarī eligibility explicit. It is not a claim that every Jyotiṣa lineage uses one setting.
Practical use
What to do with this answer
Bind each rule to its named frame and ayanāṁśa. Keep tropical results available as shared input or comparison data without feeding them into a sidereal rule silently.
Distinctions to preserve
- Registered Maha convention versus every living lineage
- Sidereal frame versus Lahiri specifically
- Calculation eligibility versus predictive validity
Limitations
- The current rule corpus is deliberately small.
- Passage and practitioner review remain separate from arithmetic reproducibility.
Authority graph
Which existing contracts carry the answer
These linked pages carry the underlying definition, method, or tradition record and its own sources. This page preserves their boundaries rather than becoming a new source of independent authority.
Vedic (Jyotiṣa) →
Establishes: The Indian sidereal system represented here by a deliberately small source-bound corpus. Its calendrical arithmetic is reproducible; every newly encoded natal, timing, mundane, or corporate interpretation remains withheld until passage fidelity and rule formalization receive scoped practitioner review.
Boundary: The registry documents a named interpretive tradition. It does not claim that any rule predicts an outcome.
Lahiri ayanāṁśa calculations →
Establishes: Lahiri ayanāṁśa is a coordinate conversion convention. Maha Celestial keeps the original tropical longitude and the applied offset so the sidereal result can be audited.
Boundary: Selecting Lahiri defines a coordinate frame. It does not prove that sidereal astrology is empirically valid or superior to another zodiac.
Vimśottarī daśā eligibility and opening balance →
Establishes: The input instant and Moon ephemeris state are shared. The 120-year sequence is a traditional timing convention rather than an astronomical cycle discovered from the ephemeris.
Boundary: Do not use tropical sign interpretations to explain a sidereal daśā result or present the absence of a tropical Vimśottarī output as evidence against tropical astrology.
Equivalent questions
These query forms resolve to this same answer identity; they are not separate claims.
- Is Vedic astrology always sidereal?
- Why does Jyotisha use ayanamsha?
- Does Vimshottari require a sidereal Moon?
- Which sidereal system does Maha use?
Non-claim
This answer is a method or tradition description. It is not a personalized reading and does not certify predictive validity, causation, medical outcomes, legal status, investment value, or guaranteed events.