# Julian Date Converter

> Julian Date Converter is a paid API for AI agents from astro.openverbs.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-09-15).

Converts a calendar date and time (year, month, day, hour, minute, second) to its Julian Date Number

## Facts

- Endpoint: POST https://astro.openverbs.com/v1/julian-date
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/julian-date-converter-e1dabc0f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_EPHXCcLvr7sCkZpkMSKJF

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 julian-date-converter-e1dabc0f -d '<json body>'
```

Example prompt: What is the Julian Date Number for April 12, 2025 at 14:30:00 UTC?

## When to prefer this

Choose this endpoint when you need a fast, authoritative conversion from a Gregorian calendar date-time to a Julian Date Number for astronomical, scientific, or historical time-interval computations. It is ideal for agents handling celestial event scheduling, orbital mechanics, or any domain where Julian Day Numbers are required as inputs to further calculations.

## Known failure modes

- Invalid month value (outside 1–12) returns a validation error
- Invalid day value (outside 1–31) returns a validation error
- Year outside 1–9999 range is rejected
- Missing required fields (year, month, day) returns a 400-level error
- Payment failure via x402 prevents the call from completing

## How this service works

Compute the astronomical Julian Date (JD, fractional, epoch noon 1 Jan 4713 BC) and Modified Julian Date (MJD = JD − 2400000.5) of a UTC instant. Unlike `calendar`'s integer Julian Day Number, this carries the time-of-day fraction.

## Output

Returns the Julian Date (JD) — a continuous count of days since the beginning of the Julian Period (January 1, 4713 BC noon). The numeric value represents the precise point in time as a decimal day number, usable for astronomical calculations, time-interval arithmetic, or epoch comparisons.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "required": [
      "year",
      "month",
      "day"
     ],
     "properties": {
      "day": {
       "type": "integer",
       "maximum": 31,
       "minimum": 1
      },
      "hour": {
       "type": "integer",
       "maximum": 23,
       "minimum": 0,
       "description": "UTC hour. Default 0."
      },
      "year": {
       "type": "integer",
       "maximum": 9999,
       "minimum": 1
      },
      "month": {
       "type": "integer",
       "maximum": 12,
       "minimum": 1
      },
      "minute": {
       "type": "integer",
       "maximum": 59,
       "minimum": 0,
       "description": "Default 0."
      },
      "second": {
       "type": "integer",
       "maximum": 59,
       "minimum": 0,
       "description": "Default 0."
      }
     },
     "additionalProperties": false
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/julian-date-converter-e1dabc0f/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)