Named Muhurta interval admission

Date: 8 October 2026. Scope: VED-007's seven named families, with source-selected alternatives and scoped VED-021/022 evidence/documentation. Abhijit/Brahma's published interfaces remain stable. The five additions are owned by moira.special_muhurta; their contract follows below.

Governing object and sources

moira.named_muhurta computes two time intervals, their solar anchors, numerical endpoint bounds and selected-rule eligibility. It supplies no generic score or complete activity judgement. Source identity, inspected pages, hashes, competing readings and the local-library search limits are in the source decision.

Policy	Executing reading and attribution
chintamani_eighth_daylight_part	Fixed Abhijit geometry. Daivajna Rama, Muhurta Chintamani, Avasthi commentary, tenth edition 2004, Vivaha 52, printed p.126: the eighth of fifteen equal divisions of actual daylight.
chintamani_wednesday_exclusion	Default eligibility rule, from Vivaha 54, printed p.127. Wednesday is excluded; the other six weekdays are not_excluded_by_selected_rule. This ritual/marriage-context rule is not a full marriage judgement or universal auspiciousness claim.
geometry_only	Caller explicitly declines weekday-rule evaluation. Eligibility is not_evaluated, while Abhijit geometry is identical.
arunadatta_fixed_ghati	Default Brahma reading: Arunadatta's Sarvangasundara on Ashtanga Hridaya, Sutrasthana 2.1. Four ghatis remaining in all seasons supplies the beginning; one muhurta is two ghatis. Compute 96 to 48 minutes before sunrise. The exact timing is commentarial, not a formula quoted from the base verse.
legacy_proportional_night_14	Explicit compatibility with Moira's existing Brahma predicate: the fourteenth of fifteen equal divisions of the preceding night. It equals 96-to-48 minutes only for a twelve-hour night. Hemadri's shorter penultimate-muhurta gloss does not independently settle seasonal scaling; this profile is not attributed to Arunadatta.

Brahma eligibility is always not_evaluated. The product does not evaluate health effects, meditative outcomes, doshas, cancellations or purpose rules. The reported daylight midpoint is not identified with actual solar meridian transit. Abhijit Muhurta and Abhijit Nakshatra are distinct objects.

Arithmetic and endpoint ownership

Let R be sunrise, S the following sunset and P the previous sunset, all UT1 Julian days. Intervals are half-open [start,end):

Window	Start	End
Abhijit	R + 7*(S-R)/15	R + 8*(S-R)/15
Fixed-ghati Brahma	R - 4/60	R - 2/60
Proportional-night Brahma	P + 13*(R-P)/15	P + 14*(R-P)/15

The engine evaluates the rational affine expressions on the exact supplied binary64 values and rounds each endpoint once. Direct anchors are treated as exact caller inputs; their astronomical accuracy is caller-owned. Dated anchors retain root brackets. Their lower/upper bounds propagate monotonically through each expression, with outward floating-point rounding.

interval.contains(jd_ut1) reports geometric membership: True in the resolved interior, False outside all possible endpoints, and None when the interval is unavailable or the query falls within endpoint uncertainty. Wednesday exclusion remains a separate field and does not erase geometry. Root brackets measure numerical resolution, not uncertainty in refraction, terrain, atmospheric conditions, Earth orientation or the source tradition.

Python ownership and strict inputs

Root moira, moira.facade and moira.vedic share the seven objects owned by moira.named_muhurta: NamedMuhurtaPolicy, NamedMuhurtaAnchor, NamedMuhurtaInterval, NamedMuhurtaResult, NamedMuhurtaDay, named_muhurta_from_solar_times and named_muhurta_for_date. The Moira facade supplies both functions as methods.

The supplied-anchor API requires finite representable sunrise_jd_ut1 and an explicit integer weekday from Monday=0 to Sunday=6. This is not the Sunday-first Vara index used elsewhere. Optional sunset_jd_ut1 must follow sunrise; optional previous_sunset_jd_ut1 must precede it. No numeric strings, booleans, nonfinite numbers or silently reordered anchors are admitted. solar_policy_applied=False records that no horizon/solver policy was used.

The dated API requires a Gregorian date (year 2 through 9998), latitude strictly between -90 and +90 degrees, east-positive longitude in [-180,180], and an explicit IANA timezone, UTC or UTC+/-HH:MM. It does not infer a timezone from coordinates. It evaluates the previous, requested and following civil dates using the existing daily-Panchanga solar discovery. Skipped dates within the required civil-boundary scope reject before reader access. There is no search for a distant seasonal sunrise.

The requested local sunrise date owns both intervals and the weekday rule. Brahma can start on the preceding civil date; its display is not clipped at midnight. DST changes affect civil displays and civil-date durations, while interval arithmetic remains UT1. Multiple requested-date sunrises are ambiguous. A refined sunrise bracket must lie wholly inside that civil date.

Horizon, clock and resource policy

The three existing PanchangaSunriseDefinition choices are admitted: rashtriya_upper_limb (default, -47/60 degrees), usno_upper_limb (-50/60 degrees), and geometric_center (0 degrees). The same selected altitude threshold defines sunrise and sunset. This uses the existing level-horizon, zero-elevation solar signal, without terrain or caller-adjustable atmospheric inputs. Local bisection refines discovered crossings; solver_tolerance_seconds is finite in [0.01,1], default 0.1. Refinement searches at most sixty seconds either side of each coarse witness. It never silently substitutes a different sunrise model.

The facade borrows its reader. The standalone dated function borrows an explicit reader=, or uses the active reader context when omitted. It does not discover/open a fresh reader outside a context. Every path restores the previous override and leaves reader closure to its owner.

NamedMuhurtaDay retains the three civil-date solar witnesses, refined anchors and endpoint civil moments. Its clock_*, Delta-T and kernel-label receipt is sampled at the requested civil date's midpoint; it is not a separate clock receipt for every root. Underlying solar evaluations use the existing reader-bound time machinery. Endpoint utc and local displays are converted from UT1 through the established civil-time conversion.

Availability is per window: Abhijit needs sunrise and following sunset; fixed Brahma needs only sunrise; legacy Brahma also needs previous sunset. Absent, multiple, unresolved or ambiguously owned events produce explicit reasons and null endpoints. The aggregate is available, partial or unavailable. Missing resources and coverage failures remain exceptions, not invented polar outcomes.

REST contract

Route	Canonical product
POST /v1/muhurta/named/direct	Supplied UT1 anchors and Monday-first weekday -> NamedMuhurtaResult
POST /v1/muhurta/named/day	Civil date, location, timezone and startup engine reader -> NamedMuhurtaDay

Both accept a typed policy object with the two selectable Brahma readings, two weekday modes, three sunrise definitions and bounded solver tolerance. Unknown fields and values reject. Date strings must be canonical YYYY-MM-DD; Unix timestamps, compact dates and datetime strings reject. Preflight runs before astronomy. Responses project canonical dataclasses; the server contains no interval or eligibility arithmetic.

Unavailable astronomy returns HTTP 200 with typed status, reasons and nulls. Invalid requests use the existing 422 validation_error envelope. Existing MuhurtaCoverageError maps to 422 muhurta_date_outside_coverage and MuhurtaResourceError to 503 muhurta_resource_unavailable. Request IDs are preserved. The operation is synchronous and bounded to three civil dates.

Compatibility and completion boundary

The legacy is_abhijit_muhurta and is_brahma_muhurta boolean arithmetic remains unchanged. Their documentation now distinguishes source-owned intervals and the proportional-night compatibility reading. The new default fixed-ghati Brahma policy does not silently change legacy callers. The compatibility profile retains the legacy proportional-night formula; its rational single-round endpoints are the canonical new-product boundary, not a promise of bitwise equality with the legacy chained-float predicate.

This admission does not integrate named windows into generic scoring, sampled search, natal overlays or activity guidance. VED-008–011 own their other families. The original two-window execution receipt retains its exact evidence and publication state; the five-name extension has its own source packet and execution receipt.

Five-name extension

SpecialMuhurtaPolicy explicitly selects:

Field	Admitted values and meaning
amrita_basis	Default sadhana_amrita_siddhi: seven weekday/nakshatra pairs from Muhurta Sadhana Samjna 78–79. Alternative kalaprakasika_amirtha: the larger Kalaprakasika XXXV weekday table. Outputs are distinctly named Amrita Siddhi and Amirtha.
godhuli_weekday_rule	Default vrindavana_visibility: Thursday requires the fully set Sun, Saturday requires it still visible. Other weekdays are not excluded by this selected rule. geometry_only declines this rule.
godhuli_horizon	Default standard_refraction_34_arcmin: centre crossing at −34/60 degrees, upper-limb sunset at −50/60 degrees. geometric_disc: centre at 0, upper-limb sunset at −16/60 degrees. Both use fixed 16 arcminute semidiameter, level horizon, zero elevation and no terrain. These are disclosed modern realizations of the textual event, not classical constants or observed atmospheric accuracy.
ayanamsa_system	Registered engine system, default Lahiri, true mode. Applied to dated geocentric apparent Sun/Moon positions; not applied again to supplied sidereal longitudes.
solar_policy	The full typed NamedMuhurtaPolicy above; governs included Abhijit/Brahma, daylight anchors and root tolerance. Its sunrise/sunset definition is independent of Godhuli's disc-event definition.

The fixed source identities are inspectable in the policy and each result:

• Vijaya: eleventh of fifteen daylight parts, from sunrise +10/15 of daylight to sunrise +11/15. It is not a fixed 14:00 clock interval or a Vijaya Dashami festival calculation.
• Godhuli: Vivaha Vrindavana 9.6 with Vasantalakshmi commentary, half a ghati either side of the half-set disc, hence ±12 elapsed minutes. Godhuli's entire geometry remains present. On Thursday/Saturday, verse 9.5's eligibility partitions it at the separate upper-limb sunset. A portion is excluded, not_excluded_by_selected_rule, or not_evaluated; lack of the visibility anchor yields partial status.
• Amrita Siddhi / Amirtha: presence while the Moon occupies a star in the selected source table for the sunrise-owned weekday. Kalaprakasika's reviewed Sunday table has no Amirtha entry; its Siddha rows are not renamed.
• Ravi Yoga: Chintamani Shubhashubha 27, inclusive Moon-star count from Sun-star in {4,6,9,10,13,20}. Both bodies' transitions can change it.
• Sarvarthasiddhi: Chintamani Shubhashubha 28–29's seven weekday tables.

The two Amrita tables, Anandadi Amrita, Choghadiya, Amrita Kalam and Nitya Yoga are distinct objects. This package implements the first two, under separate profile names. Source disagreement, especially Chintamani's season-dependent Godhuli and Moon/Lagna restrictions versus Vrindavana's reading, is documented rather than silently combined. No output claims universal auspiciousness or complete marriage/travel/construction suitability; activity_suitability is explicitly not_evaluated.

New engine and REST surfaces

Engine function / facade method	REST route	Contract
special_muhurta_from_solar_times	POST /v1/muhurta/special/solar	Optional sunrise, sunset, half-set and upper-limb-set UT1 anchors; required Monday-first weekday; canonical Vijaya/Godhuli results. Supplied anchors retain caller ownership. Missing anchors yield per-result status.
muhurta_yogas_from_longitudes	POST /v1/muhurta/special/yogas	Required Sun and Moon sidereal longitudes in [0,360), plus sunrise weekday; returns all three named presence booleans, star indices/names, inclusive count and source evidence. No reader or coordinate conversion.
special_muhurta_for_date	POST /v1/muhurta/special/day	Civil date/location/timezone with the same admission as the existing named-day route. Returns all five new results plus named, the canonical Abhijit/Brahma day, without rebuilding it in transport.

Eleven owning exports are shared by root, facade and moira.vedic. The three facade methods delegate to the owner. Strict inputs reject booleans as numbers, strings as numbers, non-finite/out-of-range coordinates, unsupported profiles, unknown fields, malformed/skipped civil dates and contradictory supplied anchors before astronomy. Partial/unavailable calculations remain HTTP 200; resource/coverage errors use the existing named-Muhurta 503/422 envelopes.

Date ownership, transition cells and uncertainty

The requested local sunrise date owns Vijaya, Godhuli, and the three yoga families. The yoga interval runs from that sunrise to the following local date's sunrise. Local midnight does not change its weekday. Discovery stays within the existing previous/current/following civil dates, with no distant seasonal substitute. Absence of the next sunrise makes yoga coverage unavailable but preserves independently computable current-day solar windows.

For yogas, hourly forward-phase bracketing and root bisection find every Sun and Moon nakshatra crossing in the sunrise day. Each phase step must be positive and less than half a nakshatra; violations fail visibly. The stopping tolerance is the policy's 0.01–1 second numerical bracket width, not a claim about observational or ephemeris accuracy. The bounded day is at most two elapsed days. No mean-speed interpolation or sampled-score interval is substituted for a root.

Results contain constant-star cells, not merged maximal intervals. Each cell has start/end nominal UT1, lower/upper brackets, civil displays and the source evidence establishing presence. status="available" with no windows means no match outside the separately reported numerical uncertainty bands. It is distinct from unavailable astronomy.

transition_bands includes uncertain sunrise ownership and star crossings. Overlapping Sun/Moon brackets are combined; possible very short occurrences wholly inside such a band remain unresolved and are not falsely asserted absent. SpecialMuhurtaDay.contains_yoga(name, jd_ut1) returns None inside these bands or when required anchors are missing. Elsewhere it returns membership in this day's selected yoga. Individual solar/yoga window contains methods likewise retain half-open geometry and endpoint uncertainty; they do not override a separate eligibility exclusion.

Every dated position and horizon evaluation borrows the same engine reader. The embedded named result preserves the kernel and civil-midpoint clock receipt; it is not presented as an independent clock measurement for every transition. Exceptions restore the caller's active-reader context.