Equinox, Solstice, Perihelion and Aphelion Dates for a Year (USNO)

usno/earth-seasons

The date and Universal Time of the two equinoxes, the two solstices, perihelion (Earth closest to the Sun) and aphelion (Earth farthest from the Sun) for a given year, as computed by the U.S. Naval Observatory. Returns six events in date order. Astronomical computation data passed through unmodified and served by Eden Engine; not an official U.S. Naval Observatory product.

activeper callv1

Price

$0.0026 per call

You pay the price shown. If a call turns out to cost more than its quote, you pay the actual price, capped at twice the quote. No monthly minimum. Top-ups start at $5.

Data source

U.S. Naval Observatory

Data from the U.S. Naval Observatory (USNO), U.S. Department of the Navy, a US federal government work in the public domain (17 USC 105); no credit is required. Served by Eden Engine; not an official U.S. Naval Observatory product.

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agent

// 1. search: find the tool
omnial_search({ query: "what you need" })

// 2. inspect: price and input schema
omnial_inspect({ tool: "usno/earth-seasons" })

// 3. learn: read the usage guide at runtime
omnial_learn({ tool: "usno/earth-seasons" })

// 4. run: price the exact call first, then run it
omnial_execute({ tool: "usno/earth-seasons", input: { /* see input_schema */ }, dry_run: true })
omnial_execute({ tool: "usno/earth-seasons", input: { /* ... */ } })

// 5. settle: the call is charged when it finishes, nothing to do

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Pricing

Every charge this tool can incur.

Charge	Price
Per call	$0.0026

Updated: Oct 20, 2026

Input and output schemas

Input schema

input_schema.json

{
  "type": "object",
  "required": [
    "year"
  ],
  "properties": {
    "year": {
      "type": "integer",
      "maximum": 2100,
      "minimum": 1700,
      "description": "The calendar year, 1700 to 2100, for example 2026."
    }
  },
  "additionalProperties": false
}

Output schema

output_schema.json

{
  "type": "object",
  "required": [
    "data"
  ],
  "properties": {
    "tz": {
      "type": "number",
      "description": "Time zone offset of the times, 0 meaning Universal Time."
    },
    "dst": {
      "type": "boolean",
      "description": "Whether daylight saving time was applied (false)."
    },
    "data": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "day": {
            "type": "integer"
          },
          "time": {
            "type": "string",
            "description": "HH:MM in Universal Time."
          },
          "year": {
            "type": "integer"
          },
          "month": {
            "type": "integer"
          },
          "phenom": {
            "type": "string",
            "description": "Perihelion, Equinox, Solstice or Aphelion."
          }
        },
        "additionalProperties": true
      },
      "description": "The six events in date order."
    },
    "year": {
      "type": "integer",
      "description": "The year computed."
    },
    "apiversion": {
      "type": "string",
      "description": "USNO API version that produced the data."
    }
  },
  "description": "The USNO seasons response.",
  "additionalProperties": true
}