# Moon Phase Lookup by Date

> Moon Phase Lookup by Date is a paid API for AI agents from api.vextorium.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-10-19).

Returns the moon phase name, illumination percentage, lunar age, and next new/full moon dates for a given calendar date.

## Facts

- Endpoint: POST https://api.vextorium.com/v1/moon-phase?utm_source=zero.xyz
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-19
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/moon-phase-lookup-by-date-585f2730
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_9fFclsCQdma6lHHhkWdjD

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 moon-phase-lookup-by-date-585f2730 -d '<json body>'
```

Example prompt: What's the moon phase on October 31st, 2025? I want to know the phase name, how illuminated it is, its lunar age, and when the next new and full moons will be after that date.

## When to prefer this

Choose this endpoint when you need quick, locally-computed lunar phase data for any calendar date without relying on external astronomy APIs. It is ideal for date-specific lookups where exact phase transitions are needed and a ±1 day accuracy margin is acceptable. Prefer this over ephemeris-based services when low latency and low cost matter more than sub-hour precision.

## Known failure modes

- Invalid date format (non-YYYY-MM-DD string) may return an error or default to today
- Dates extremely far in the past or future may produce inaccurate results due to mean calculation approximations
- Missing body may default to today's date rather than returning an error
- Network timeout on payment verification

## How this service works

Moon phase on a date: name, illuminated percentage, lunar age and the next new and full moon dates. Local astronomical calculation.

## Output

A JSON object containing: the queried date, the moon phase name (e.g. 'last quarter', 'full moon'), illumination percentage, lunar age in days, next new moon date, next full moon date, and a note indicating calculation accuracy (±1 day on phase dates).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "date": {
   "type": "string",
   "description": "YYYY-MM-DD (default today)"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "date": "2026-10-02",
  "note": "Mean calculation (±1 day on phase dates).",
  "phase": "last quarter",
  "age_days": 20.97,
  "next_new_moon": "2026-10-11",
  "next_full_moon": "2026-10-26",
  "illumination_pct": 62.4
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/moon-phase-lookup-by-date-585f2730/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.vextorium.com](https://www.zero.xyz/host/api.vextorium.com/llms.txt)