---
title: "Search bounded global solar and lunar eclipse geometry"
method: POST
path: "/api/astro/eclipse-geometry"
tags: ["Calculations"]
---

# Search bounded global solar and lunar eclipse geometry

`POST /api/astro/eclipse-geometry`

## Request

- Base URL: `https://api.cosmicephemeris.com`
- URL: `https://api.cosmicephemeris.com/api/astro/eclipse-geometry`
- Auth: one of:
  - HTTP bearer
  - API key in header `x-api-key`

Returns global/geocentric solar shadow-cone geometry and Skyfield Danjon lunar-shadow geometry over a maximum 366-day UTC interval. Optional observer coordinates add one fixed WGS84 sea-level, no-refraction topocentric snapshot at each event's rounded global maximum. The snapshot is not a local-maximum or contact-time solver and does not establish visibility at other instants. No path, map, terrain, weather, eye-safety guidance or interpretation is provided. One standard quota unit per admitted request; failed or timed-out admitted attempts are not refunded.
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.

## Request body

- union
  - EclipseGeometryRequest
    - `start_utc` string, date-time, required: Normalized UTC timestamp; fractional seconds may be present.
    - `end_utc` string, date-time, required: Normalized UTC timestamp; fractional seconds may be present.
    - `eclipse_types` EclipseType[], required
    - `observer` GeographicLocation: Geographic coordinates in decimal degrees. The server rejects exactly -90 and +90 latitude because angles and houses are undefined at the poles.
      - `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
  - HistoricalEclipseGeometryRequest: 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.
    - `eclipse_types` string[], required
    - `observer` object: Geographic coordinates in decimal degrees. The server rejects exactly -90 and +90 latitude because angles and houses are undefined at the poles.
      - `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
    - `start` HistoricalDateTime, required: Shared historical input contract; parsing alone does not enable a calculation route. Derived calculation records can include fractional seconds and are not this input type.
      - `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: Explicit HH:MM[:SS]; whole seconds only, no leap seconds. Normalized helper output includes seconds.
      - `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.
    - `end` HistoricalDateTime, required: Shared historical input contract; parsing alone does not enable a calculation route. Derived calculation records can include fractional seconds and are not this input type.
      - `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: Explicit HH:MM[:SS]; whole seconds only, no leap seconds. Normalized helper output includes seconds.
      - `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.

## Response `200`

Chronological bounded global eclipse geometry.

- union
  - EclipseGeometryResponse
    - `type` 'eclipse_geometry', required
    - `status` 'current', required
    - `input` object, required
    - `events` EclipseEvent[], required
      - `eclipse_type` 'solar' | 'lunar', required
      - `kind` 'partial' | 'total' | 'annular' | 'hybrid' | 'penumbral', required
      - `maximum_utc` string, date-time, required: Normalized UTC timestamp; fractional seconds may be present.
      - `geometry` object, required: Solar shadow-cone distances/radii or lunar angular shadow radii/magnitudes, according to eclipse_type.
      - `observer_snapshot` EclipseObserverSnapshot
        - `reference_instant` 'rounded_global_maximum', required
        - `eclipsed_body` 'sun' | 'moon', required
        - `eclipsed_body_center_altitude_degrees` number, required
        - `eclipsed_body_center_azimuth_degrees` number, required
        - `eclipsed_body_angular_radius_degrees` number, required
        - `eclipsed_body_upper_limb_altitude_degrees` number, required
        - `above_geometric_horizon_at_snapshot` boolean, required
        - `solar_moon_center_altitude_degrees` number, nullable, required
        - `solar_moon_center_azimuth_degrees` number, nullable, required
        - `solar_moon_angular_radius_degrees` number, nullable, required
        - `solar_sun_moon_separation_degrees` number, nullable, required
        - `solar_disks_overlap_at_snapshot` boolean, nullable, required
        - `eclipse_geometry_visible_at_snapshot` boolean, required: For solar events, geometric disk overlap and the Sun's upper limb above the geometric horizon at this snapshot; for lunar events, the Moon's upper limb above the geometric horizon. It is not a claim about visibility at any other instant, weather, terrain, refraction, or safe viewing.
    - `event_count` integer, required
    - `metadata` object, required
  - HistoricalEclipseGeometryEclipseGeometryResponse
    - `schema` 'cosmicephemeris-historical-calculation-v1', required
    - `status` 'historical', required
    - `type` 'eclipse-geometry', required
    - `input` HistoricalEclipseGeometryRequest, 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.
      - `eclipse_types` string[], required
      - `observer` object: Geographic coordinates in decimal degrees. The server rejects exactly -90 and +90 latitude because angles and houses are undefined at the poles.
        - `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
      - `start` HistoricalDateTime, required: Shared historical input contract; parsing alone does not enable a calculation route. Derived calculation records can include fractional seconds and are not this input type.
        - `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: Explicit HH:MM[:SS]; whole seconds only, no leap seconds. Normalized helper output includes seconds.
        - `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.
      - `end` HistoricalDateTime, required: Shared historical input contract; parsing alone does not enable a calculation route. Derived calculation records can include fractional seconds and are not this input type.
        - `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: Explicit HH:MM[:SS]; whole seconds only, no leap seconds. Normalized helper output includes seconds.
        - `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.
    - `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)