Astronomy

Telescope Field of View Calculator

Compute telescope optics for visual astronomy: magnification, true field of view, focal ratio, exit pupil, limiting magnitude, Dawes/Rayleigh resolution and useful-magnification range. Enter aperture, telescope focal length, an eyepiece focal length and its AFOV (metric mm or imperial inches), pick a target (deep-sky, planetary, lunar or terrestrial), and get a scaled field-of-view overlay plus target-specific advice on exit pupil and framing.

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Quick start

Call this tool from your code in three languages.

cURL

curl -X POST 'https://api.elysiatools.com/en/api/tools/telescope-field-of-view-calculator' \
  -H 'Content-Type: application/json' \
  -d '{"aperture":203,"focalLength":2032,"eyepiece":25,"afov":60,"units":"metric","target":"deepsky","distance":0,"showOverlay":true}'

API reference

Send a POST request with your inputs as JSON. File parameters require a separate upload first.

Endpoint

HTTP

POST https://api.elysiatools.com/en/api/tools/telescope-field-of-view-calculator

Parameters

Name	Type	Required	Description
aperture	number	Yes	—
focalLength	number	Yes	—
eyepiece	number	Yes	—
afov	number	Yes	—
units	select	No	—
target

MCP integration

Add this tool to your Model Context Protocol server so AI agents can list and call it.

Server configuration

Add this block to your MCP client configuration:

mcp.json

{
  "mcpServers": {
    "elysiatools-telescope-field-of-view-calculator": {
      "name": "telescope-field-of-view-calculator",
      "description": "Compute telescope optics for visual astronomy: magnification, true field of view, focal ratio, exit pupil, limiting magnitude, Dawes/Rayleigh resolution and useful-magnification range. Enter aperture, telescope focal length, an eyepiece focal length and its AFOV (metric mm or imperial inches), pick a target (deep-sky, planetary, lunar or terrestrial), and get a scaled field-of-view overlay plus target-specific advice on exit pupil and framing.",
      "baseUrl": "https://api.elysiatools.com/mcp/sse?toolId=telescope-field-of-view-calculator",
      "command": "",
      "args": [],
      "env": {},
      "isActive": true,
      "type": "sse"
    }
  }
}

List available tools

After connecting to the SSE endpoint, list the exposed tools:

tools/list

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/list"
}

Call this tool

Invoke the tool by its id, passing arguments built from its parameters:

tools/call

{
  "jsonrpc": "2.0",
  "id": 2,
  "method": "tools/call",
  "params": {
    "name": "telescope-field-of-view-calculator",
    "arguments": {
  "aperture": 203,
  "focalLength": 2032,
  "eyepiece": 25,
  "afov": 60,
  "units": "metric",
  "target": "deepsky",
  "distance": 0,
  "showOverlay": true
}
  }
}

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