# Astronomy Season Lookup

> Astronomy Season Lookup is a paid API for AI agents from astro.openverbs.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-14).

Returns the astronomical season (spring, summer, autumn, winter) for a given date and hemisphere

## Facts

- Endpoint: POST https://astro.openverbs.com/v1/season
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/astronomy-season-lookup-fd6a6bd0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_a1AGcjcB9GjF3jYbbDubK

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability astronomy-season-lookup-fd6a6bd0 -d '<json body>'
```

Example prompt: What astronomical season is it on June 21, 2025 in the northern hemisphere?

## When to prefer this

Use this endpoint when you need a quick, reliable lookup of the astronomical season for any specific date and hemisphere. It is ideal for date-aware applications, scheduling tools, or any agent that needs to contextualize a date within a seasonal framework without performing manual solstice/equinox calculations. Prefer this over manual computation or general-purpose calendar APIs when you specifically need astronomical (not meteorological) seasons.

## Known failure modes

- Invalid date values (day > 31, month > 12) return validation error
- Missing required fields (year, month, day) cause request rejection
- Invalid hemisphere value (not 'northern' or 'southern') may cause error
- Payment failure via x402 protocol prevents access
- Year out of range (below 1 or above 9999) triggers schema validation error

## How this service works

Determine the astronomical season for a date, based on the Sun's apparent ecliptic longitude (0°=March equinox, 90°=June solstice, …). Defaults to the northern hemisphere; pass `hemisphere` to flip.

## Output

The endpoint returns the astronomical season (e.g. spring, summer, autumn, or winter) corresponding to the provided date and hemisphere, based on standard astronomical season boundaries (solstices and equinoxes).

## Request schema (JSON Schema)

```json
{
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "type": "object",
 "properties": {
  "input": {
   "type": "object",
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "type": "string",
     "enum": [
      "POST"
     ]
    },
    "bodyType": {
     "type": "string",
     "enum": [
      "json",
      "form-data",
      "text"
     ]
    },
    "body": {
     "type": "object",
     "properties": {
      "year": {
       "type": "integer",
       "minimum": 1,
       "maximum": 9999
      },
      "month": {
       "type": "integer",
       "minimum": 1,
       "maximum": 12
      },
      "day": {
       "type": "integer",
       "minimum": 1,
       "maximum": 31
      },
      "hemisphere": {
       "type": "string",
       "enum": [
        "northern",
        "southern"
       ],
       "description": "Default northern."
      }
     },
     "required": [
      "year",
      "month",
      "day"
     ],
     "additionalProperties": false
    }
   },
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "additionalProperties": false
  }
 },
 "required": [
  "input"
 ]
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/astronomy-season-lookup-fd6a6bd0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from astro.openverbs.com](https://www.zero.xyz/host/astro.openverbs.com/llms.txt)