Varāhamihira graded five dead rivals honestly

Status: Anticipated · untested

Status is derived only from the shepherd-authored triage/prediction data above -- community submissions and claims are a separate overlay and can never change it (see the participation panel below).

This is a proposed connection between two domains, generated by a language model. It is not an article and not evidence: it sits below the evidence/publication boundary. A quantitative prediction and a named kill-dataset are attached (when registered) so the claim stays falsifiable rather than merely evocative.

Claim (verbatim)

Five early astronomical systems — the Paitāmaha, Vāsiṣṭha, Romaka, Pauliśa, and Saura siddhāntas — are lost in their originals (the extant Sūryasiddhānta is a later, different text); the only quantitative access to them is Varāhamihira's Pañcasiddhāntikā (sixth century, Ujjain), a comparative digest that not only summarizes but grades them (I.4): the Pauliśa accurate, the Romaka near it, the Saura more accurate still, the remaining two far from the truth. A doxographer could rank by school loyalty at no cost; an astronomer publishing a ranking of working systems risks the sky contradicting him. If Varāhamihira's grades were empirical, then lost-text testimony can be audited a millennium and a half later: reimplement each summarized system and score it against the real sky of his own epoch. Prediction: implementing each of the five systems' solar and lunar algorithms as edited from the Pañcasiddhāntikā and scoring positional error against a modern ephemeris for dates around the treatise's epoch (505 CE, Ujjain meridian), the accuracy ordering will reproduce Varāhamihira's published grading — Saura best, Pauliśa and Romaka next, Vāsiṣṭha and Paitāmaha worst — with the Saura's mean solar-longitude error under half the Paitāmaha's (primary clause: the ordering match on the solar theory; the verdict follows it). Kill: the algorithms as edited in O. Neugebauer and D. Pingree, The Pañcasiddhāntikā of Varāhamihira (Copenhagen, 1970-71), controlled against the Kuppanna Sastri-Sarma edition (1993), run against the JPL DE ephemerides.

Prediction clause (verbatim)

Prediction: implementing each of the five systems' solar and lunar algorithms as edited from the Pañcasiddhāntikā and scoring positional error against a modern ephemeris for dates around the treatise's epoch (505 CE, Ujjain meridian), the accuracy ordering will reproduce Varāhamihira's published grading — Saura best, Pauliśa and Romaka next, Vāsiṣṭha and Paitāmaha worst — with the Saura's mean solar-longitude error under half the Paitāmaha's (primary clause: the ordering match on the solar theory; the verdict follows it).

Kill-dataset (verbatim)

Kill: the algorithms as edited in O. Neugebauer and D. Pingree, The Pañcasiddhāntikā of Varāhamihira (Copenhagen, 1970-71), controlled against the Kuppanna Sastri-Sarma edition (1993), run against the JPL DE ephemerides.

Nobody has run this test. The kill-data is named above. If you can run it — or you know the paper that already settles it — claim the kill or submit the prior scholarship. Kills and prior scholarship are credited here, by name, as they come in.

Provenance

Run: Fresh agent generation · model: claude-fable-5

Fresh blind generation by claude-fable-5, 2026-07-16, breadth wave weighting India/South Asia by inferred textual production rather than survival; every item grounded in real works, authors, catalogues, and testimonia, including the real evidence of loss (citing authors, catalogue entries, translation corpora, rediscovery cases); no fabricated citations.

Novelty / leakage triage

anticipated in the literature — this exact test has never been run

Billard's programme scored Indian canons against modern ephemerides via deviation curves (including material related to the early Suryasiddhanta), and the Neugebauer-Pingree edition discusses the five systems' quality qualitatively — Varahamihira's own grading is famous. But a reimplementation of all five Pancasiddhantika systems scored against the c. 505 CE sky to audit that grading as an ordering test was not located.

O. Neugebauer and D. Pingree, The Pancasiddhantika of Varahamihira, 2 vols. (Copenhagen, 1970-71)
R. Billard, L'astronomie indienne: investigation des textes sanskrits et des donnees numeriques (EFEO, Paris, 1971)

Predictions

Open registered 2026-07-17 calibration prediction (parent triage: leaked/adjacent)

Registered against the five siddhanta solar algorithms as edited in the Pancasiddhantika, scored vs a modern ephemeris. Claim under test (primary clause): the empirical solar-accuracy ORDERING of the five systems reproduces Varahamihira's own published grading (Saura best; Pauliza, Romaka next; Vaziztha, Paitamaha worst), with the Saura's mean solar-longitude error under HALF the Paitamaha's.

Resolution criteria: DATA: the solar-longitude algorithms of the Paitamaha, Vaziztha, Romaka, Pauliza and Saura siddhantas as edited in O. Neugebauer & D. Pingree, The Pancasiddhantika of Varahamihira (Copenhagen 1970-71), controlled against Kuppanna Sastri-Sarma (1993); true solar longitudes from a JPL DE ephemeris at the Ujjain meridian. FEASIBILITY GUARD (evaluate FIRST): the Neugebauer-Pingree edition is a PRINT critical edition; if the five systems' solar algorithms are NOT available in an open/digitized form sufficient to implement them faithfully, the kill-dataset is not buildable as registered -> INCONCLUSIVE_BY_DESIGN (do not reconstruct the algorithms from secondary paraphrase). METRIC (if buildable): implement each system's solar-longitude computation; compute mean absolute error vs the ephemeris over a set of dates spanning ~505 CE (the treatise epoch). PRIMARY: does the best->worst ordering match Varahamihira's grading AND is mean_error(Saura) < 0.5 * mean_error(Paitamaha)? CLAUSE PRECEDENCE: (1) INCONCLUSIVE_BY_DESIGN per the feasibility guard, or if the algorithms cannot be implemented unambiguously. (2) SUPPORTED if the ordering matches and the Saura<0.5*Paitamaha condition holds. (3) KILLED otherwise. Report each system's mean error, the ordering, and the algorithm source actually used. computed_at postdates registered_at.

Known priors disclosure: Held: the conjecture's reasoning (Varahamihira graded five now-lost systems and the grading should be empirically checkable) and general knowledge the Pancasiddhantika is the sole quantitative access to the lost originals. NOT computed: any accuracy figure. HONESTLY FLAGGED at registration: the edition is print, so this may resolve INCONCLUSIVE_BY_DESIGN (algorithms not openly buildable) rather than supported/killed.

Weigh in

No community feedback yet.

New here? Create an account first

Create an account or sign in and your feedback is tied to you — you can track it, get replies, and claim this conjecture so others know you’re working on it. Prefer not to? Just leave your take below as a guest — only the name you type is shown.

Add your take

Posted immediately (spam is removed). Community feedback is never an adjudicated verdict and never changes this conjecture's triage label or status above.