# Runic Calendar (runstaff)

`POST https://api.astroway.info/v1/runes/calendar`

The medieval Scandinavian runic calendar for a date: the day rune (fé, úr, þurs, óss, reið, kaun, hagall for letters A-G from 1 January), the year's Sunday rune or runes (the dominical letter, two in a leap year) and the golden-number rune of the 19-year lunar cycle (the sixteen Younger Futhark runes plus arlaug, tvímaðr, belgþór).

Group: Elder Futhark Runes. Auth: `X-Api-Key` header. Operation ID: `runes_calendar`.

## Parameters

| Name | In | Required | Type | Description |
|---|---|---|---|---|
| `fields` | query | no | string | Comma-separated dotted paths, relative to `data`, to keep in the response. A path is applied to every element of an array, so `planets.name` means the name of each planet. Paths that match nothing come back in `_fields_unmatched`; a list where nothing matches at all is a 400, because an empty object would be a confident wrong answer. |
| `precision` | query | no | integer | Round every non-integer number in the response to this many decimal places. Integers are left alone, because an id is not a measurement. Ecliptic longitudes ship with fourteen decimals by default; 2 is about a tenth of an arcminute. |
| `Idempotency-Key` | header | no | string | Unique per logical operation, kept across retries. For 24 hours from the first request, a repeat with the same key, method, path, body and query string returns the stored response with `Idempotent-Replayed: true` and costs 0 credits. The same key with a different body or query string is a 409 `IDEMPOTENCY_KEY_REUSED`; a repeat while the first is still running is a 409 `IDEMPOTENCY_IN_PROGRESS`. Only 2xx responses are kept. See /idempotency/. |

## Request body

| Field | Type | Required | Description |
|---|---|---|---|
| `date` | string | no | YYYY-MM-DD; today (UTC) when omitted. |

```json
{
  "date": "2026-11-07"
}
```

## Responses

| Status | Meaning |
|---|---|
| 200 | Successful calculation |
| 400 | Validation error |
| 401 | Missing or invalid API key |

### Success fields, under `data`

| Field | Type | Required | Description |
|---|---|---|---|
| `date` | string | no |  |
| `weekday` | string | no |  |
| `dayRune` | object | no |  |
| `dayRune.letter` | string | no |  |
| `dayRune.rune` | string | no |  |
| `dayRune.name` | string | no |  |
| `dayRune.dayOfYearCommon` | number | no |  |
| `sundayRunes` | object[] | no |  |
| `sundayRuneInForce` | object | no |  |
| `sundayRuneInForce.letter` | string | no |  |
| `sundayRuneInForce.rune` | string | no |  |
| `sundayRuneInForce.name` | string | no |  |
| `goldenNumber` | object | no |  |
| `goldenNumber.number` | number | no |  |
| `goldenNumber.rune` | string | no |  |
| `goldenNumber.name` | string | no |  |
| `notes` | string[] | no |  |
| `source` | string | no |  |

## Example

```bash
curl -X POST https://api.astroway.info/v1/runes/calendar \
  -H "X-Api-Key: aw_live_..." \
  -H "Content-Type: application/json" \
  -d '{ "date": "2026-11-07" }'
```

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Rendered from https://api.astroway.info/v1/openapi.json. HTML page: https://api.astroway.info/docs/api/operations/runes_calendar/