--- title: "Separate birth-time and convention sensitivity" method: POST path: "/api/astro/chart-robustness" tags: ["Calculations"] --- # Separate birth-time and convention sensitivity `POST /api/astro/chart-robustness` ## Request - Base URL: `https://api.cosmicephemeris.com` - URL: `https://api.cosmicephemeris.com/api/astro/chart-robustness` - Auth: one of: - HTTP bearer - API key in header `x-api-key` Evaluates 22 sign and house facts over one shared UTC sample grid and two or three explicit convention profiles. Each fact is classified as stable, time-sensitive, convention-sensitive, or sensitive to both. Unknown time uses 25 samples across the complete local civil date; approximate time accepts symmetric 10–120 minute uncertainty in ten-minute increments. Results are sampled evidence, not statistical confidence, rectification, interpretation, prediction, or a ranking of conventions. One standard quota unit per admitted request; failed or timed-out admitted attempts are not refunded. Do not automatically retry. Historical mode uses an explicit BCE/CE date object and UT1 conventions. Its response is the versioned historical envelope, not the modern UTC envelope. Read result for calculation fields and metadata for limits and uncertainty. ## Headers - `X-Cosmic-Ephemeris-Receipt` 'v1' ## Request body - union - ChartRobustnessRequest - `birth_time` union, required - object - `status` 'unknown', required - `date` string, date, required: Valid Gregorian YYYY-MM-DD local civil date, inclusive 1800-01-01 through 2200-12-31. Calendar validity and timezone conversion are checked by the server. - `timezone` string, nullable, required: IANA timezone name (for example America/New_York). Omission, null, or empty string means UTC for a birth input. Nonexistent or ambiguous local clock-change times return 400; provide the known UTC date/time with timezone UTC instead. - object - `status` 'approximate', required - `date` string, date, required: Valid Gregorian YYYY-MM-DD local civil date, inclusive 1800-01-01 through 2200-12-31. Calendar validity and timezone conversion are checked by the server. - `time` string, required: HH:MM or HH:MM:SS; no offset in this field. Use timezone to select the civil-time zone. - `timezone` string, nullable, required: IANA timezone name (for example America/New_York). Omission, null, or empty string means UTC for a birth input. Nonexistent or ambiguous local clock-change times return 400; provide the known UTC date/time with timezone UTC instead. - `uncertainty_minutes` integer, required - `lat` union, required: WGS84 decimal latitude. JSON numbers are recommended; numeric strings are accepted by the current engine, then checked for finiteness/range. Exact poles and undefined Ascendant geometry return 400; supported successful latitude is strictly between -90 and 90. Boolean/null/object/array coordinates are invalid. - number - string - `lon` union, required: WGS84 decimal longitude, east positive, within [-180,180]. JSON numbers are recommended; numeric strings are accepted then checked for finiteness/range. - number - string - `profiles` ConventionProfile[], required - `zodiac` 'tropical' | 'sidereal', required - `ayanamsa` 'lahiri' | 'raman' | 'krishnamurti' | 'fagan_bradley' | 'yukteshwar' | 'sassanian' | 'true_chitra' | 'true_revati' | 'true_pushya' | 'galactic_center_0_sagittarius' | 'galactic_alignment_mardyks' - `house_system` 'equal' | 'whole_sign' | 'placidus', required - HistoricalChartRobustnessRequest: Explicit historical mode, 1000 BCE (BC)–2500 CE (AD). No year zero, implicit calendar, UTC or IANA zone. Preserve tool-specific mathematical, geographic and search limits; calendar/time conventions and estimated Delta-T are not certified historical accuracy. - `birth_time` union, required - object - `status` 'unknown', required - `date` HistoricalDate, required: Explicit civil date, 1000 BCE (BC)–2500 CE (AD); no year zero. Calendar validity is checked by the server. Available only on documented connected historical operations, with explicit UT1/fixed-offset conventions. - `year` integer, required - `era` 'BCE' | 'CE', required: Display BCE (BC) / CE (AD); API values remain BCE / CE. No year zero. - `month` integer, required - `day` integer, required - `calendar` 'proleptic_gregorian' | 'proleptic_julian', required: Explicit choice; applies the selected calendar rules throughout history without a regional adoption switch. - `timezone` string, required: Explicit UT1 or fixed offset UT1+/-HH:MM[:SS], within 14 hours. Local clock minus offset yields UT1, not UTC. No IANA timezone inference. Original offset spelling is preserved. - object - `status` 'approximate', required - `date` HistoricalDate, required: Explicit civil date, 1000 BCE (BC)–2500 CE (AD); no year zero. Calendar validity is checked by the server. Available only on documented connected historical operations, with explicit UT1/fixed-offset conventions. - `year` integer, required - `era` 'BCE' | 'CE', required: Display BCE (BC) / CE (AD); API values remain BCE / CE. No year zero. - `month` integer, required - `day` integer, required - `calendar` 'proleptic_gregorian' | 'proleptic_julian', required: Explicit choice; applies the selected calendar rules throughout history without a regional adoption switch. - `time` string, required: HH:MM or HH:MM:SS; no offset in this field. Use timezone to select the civil-time zone. - `timezone` string, required: Explicit UT1 or fixed offset UT1+/-HH:MM[:SS], within 14 hours. Local clock minus offset yields UT1, not UTC. No IANA timezone inference. Original offset spelling is preserved. - `uncertainty_minutes` integer, required - `lat` union, required: WGS84 decimal latitude. JSON numbers are recommended; numeric strings are accepted by the current engine, then checked for finiteness/range. Exact poles and undefined Ascendant geometry return 400; supported successful latitude is strictly between -90 and 90. Boolean/null/object/array coordinates are invalid. - number - string - `lon` union, required: WGS84 decimal longitude, east positive, within [-180,180]. JSON numbers are recommended; numeric strings are accepted then checked for finiteness/range. - number - string - `profiles` object[], required - `zodiac` 'tropical' | 'sidereal', required - `ayanamsa` 'lahiri' | 'raman' | 'krishnamurti' | 'fagan_bradley' | 'yukteshwar' | 'sassanian' | 'true_chitra' | 'true_revati' | 'true_pushya' | 'galactic_center_0_sagittarius' | 'galactic_alignment_mardyks' - `house_system` 'equal' | 'whole_sign' | 'placidus', required ## Response `200` Bounded two-axis robustness evidence - union - ChartRobustnessResponse - `type` 'chart_robustness', required - `status` 'current', required - `workflow` object, required - `profiles` object[], required - `summary` object, required - `facts` ChartRobustnessFact[], required - `id` string, required - `point` string, required - `fact` 'sign' | 'house', required - `classification` 'stable' | 'time_sensitive' | 'convention_sensitive' | 'time_and_convention_sensitive', required - `stable_across_matrix` boolean, required - `time_sensitive` boolean, required - `convention_sensitive` boolean, required - `observed_values` unknown[], required - unknown - `dominant_sample_ratio` number, required - `profiles` object[], required - `evidence` object, required - `metadata` object, required - `receipt` CalculationReceipt - `schema` 'cosmicephemeris-calculation-receipt-v1', required - `kid` string, required - `algorithm` 'Ed25519', required - `canonicalization` 'cosmicephemeris-canonical-data-v1', required - `input_normalization` 'public-request-canonical-data-v1', required - `route` string, required - `release` string, required - `issued_at` string, date-time, required - `normalized_input_sha256` string, required - `result_sha256` string, required - `calculation_profile` object, required - `service_dataset_versions` object, required - `calculation_fingerprint` string, required - `verification_uri` string, required - `signature` string, required - HistoricalChartRobustnessChartRobustnessResponse - `schema` 'cosmicephemeris-historical-calculation-v1', required - `status` 'historical', required - `type` 'chart-robustness', required - `input` HistoricalChartRobustnessRequest, required: Explicit historical mode, 1000 BCE (BC)–2500 CE (AD). No year zero, implicit calendar, UTC or IANA zone. Preserve tool-specific mathematical, geographic and search limits; calendar/time conventions and estimated Delta-T are not certified historical accuracy. - `birth_time` union, required - object - `status` 'unknown', required - `date` HistoricalDate, required: Explicit civil date, 1000 BCE (BC)–2500 CE (AD); no year zero. Calendar validity is checked by the server. Available only on documented connected historical operations, with explicit UT1/fixed-offset conventions. - `year` integer, required - `era` 'BCE' | 'CE', required: Display BCE (BC) / CE (AD); API values remain BCE / CE. No year zero. - `month` integer, required - `day` integer, required - `calendar` 'proleptic_gregorian' | 'proleptic_julian', required: Explicit choice; applies the selected calendar rules throughout history without a regional adoption switch. - `timezone` string, required: Explicit UT1 or fixed offset UT1+/-HH:MM[:SS], within 14 hours. Local clock minus offset yields UT1, not UTC. No IANA timezone inference. Original offset spelling is preserved. - object - `status` 'approximate', required - `date` HistoricalDate, required: Explicit civil date, 1000 BCE (BC)–2500 CE (AD); no year zero. Calendar validity is checked by the server. Available only on documented connected historical operations, with explicit UT1/fixed-offset conventions. - `year` integer, required - `era` 'BCE' | 'CE', required: Display BCE (BC) / CE (AD); API values remain BCE / CE. No year zero. - `month` integer, required - `day` integer, required - `calendar` 'proleptic_gregorian' | 'proleptic_julian', required: Explicit choice; applies the selected calendar rules throughout history without a regional adoption switch. - `time` string, required: HH:MM or HH:MM:SS; no offset in this field. Use timezone to select the civil-time zone. - `timezone` string, required: Explicit UT1 or fixed offset UT1+/-HH:MM[:SS], within 14 hours. Local clock minus offset yields UT1, not UTC. No IANA timezone inference. Original offset spelling is preserved. - `uncertainty_minutes` integer, required - `lat` union, required: WGS84 decimal latitude. JSON numbers are recommended; numeric strings are accepted by the current engine, then checked for finiteness/range. Exact poles and undefined Ascendant geometry return 400; supported successful latitude is strictly between -90 and 90. Boolean/null/object/array coordinates are invalid. - number - string - `lon` union, required: WGS84 decimal longitude, east positive, within [-180,180]. JSON numbers are recommended; numeric strings are accepted then checked for finiteness/range. - number - string - `profiles` object[], required - `zodiac` 'tropical' | 'sidereal', required - `ayanamsa` 'lahiri' | 'raman' | 'krishnamurti' | 'fagan_bradley' | 'yukteshwar' | 'sassanian' | 'true_chitra' | 'true_revati' | 'true_pushya' | 'galactic_center_0_sagittarius' | 'galactic_alignment_mardyks' - `house_system` 'equal' | 'whole_sign' | 'placidus', required - `result` object, required: Complete historical calculation adapter result. Times are explicit UT1 date records, never UTC strings; derived times may include fractional seconds and years outside the input range. - `metadata` object, required - `time_standard` 'UT1', required - `historical_accuracy_certified` unknown, required - `warnings` string[], required ## Other responses - `400`: Invalid request, malformed JSON, out-of-range date/location, unknown model, invalid timezone or ambiguous/nonexistent clock-change time. Invalid attempts reaching quota reservation consume one unit. - `401`: Missing, invalid, revoked API key or unavailable activated key owner. Dashboard cookies do not authenticate calculation routes. - `403`: Origin not allowed by production CORS policy. Server-to-server requests can omit Origin. - `429`: Monthly quota exhausted, per-user two-request concurrency reached, or nginx rate/connection admission refused. Retry-After: 2 is sent for application per-user concurrency only, not a promise that monthly quota resets in two seconds. - `502`: Engine unavailable, unsuccessful internal server response or invalid upstream JSON. No engine internals are exposed. - `503`: Four-request global calculation pool full (Retry-After: 2), maintenance or upstream service unavailable. - `504`: Application engine timeout: 15 seconds normally; planetary events, house ingresses, aspect windows, event calendar, eclipse geometry, electional search, and event-rule search use 30 seconds; Nakshatra Timeline plus the explicitly enumerated readiness, robustness, location, uncertainty, and electional-audit family use 60 seconds. Timer includes response-body parsing; an admitted timeout consumes quota. --- [API](https://skmtc.dev/cosmicephemeris/apis/cosmic-ephemeris-calculation-api.md) · [All operations](https://skmtc.dev/cosmicephemeris/apis/cosmic-ephemeris-calculation-api/llms.txt) · [OpenAPI document](https://skmtc.dev/cosmicephemeris/apis/cosmic-ephemeris-calculation-api/revisions/f041e924cea3?raw)