Overview
The Minor Planet Center API (via Asterank) gives you access to data about asteroids, comets, and other small solar system bodies. It returns orbital parameters, estimated value, and other scientific data in an easy-to-use format. No API key is needed, making it a great choice for space enthusiasts learning to work with astronomical data.
Beginner Tip
Use the "limit" query parameter to keep initial responses small — start with limit=5 so you can read through the JSON structure without being overwhelmed.
Measurement Record
What actually happened when we called this API from our own infrastructure. Every value below was recorded by the request, not copied from the provider's documentation.
- Request
- GET http://www.asterank.com/api/mpc?query={%22e%22:{%22%24lt%22:0.1}}&limit=5
- Result
- HTTP 200 · application/json · 1,857 bytes · compressed
- Response time
- 211 ms (median of 3) · fastest 199 ms
- Browser CORS
- Allowed — Access-Control-Allow-Origin: *
- Served by
- cloudflare
- Recorded
- 2026-08-10
Fields Returned
Top-level fields present in the response we captured, with the type and value we actually received.
| Field | Type | Value received |
|---|---|---|
| rms | number | 0.6 |
| epoch | string | K194R |
| readable_des | string | (1) Ceres |
| H | number | 3.34 |
| num_obs | integer | 6725 |
| ref | string | MPO452155 |
| G | number | 0.12 |
| last_obs | string | 20180430 |
| comp | string | MPCLINUX |
| M | number | 77.37215 |
| U | string | |
| e | number | 0.0760091 |
| a | number | 2.7691652 |
| om | number | 80.30553 |
Captured Response
Captured from a real request to http://www.asterank.com/api/mpc?query={%22e%22:{%22%24lt%22:0.1}}&limit=5 on 2026-08-10. Long arrays and nested objects are truncated to keep the shape readable.
[
{
"rms": 0.6,
"epoch": "K194R",
"readable_des": "(1) Ceres",
"H": 3.34,
"num_obs": 6725,
"ref": "MPO452155",
"G": 0.12,
"last_obs": "20180430",
"comp": "MPCLINUX ",
"M": 77.37215,
"U": " ",
"e": 0.0760091,
"a": 2.7691652,
"om": 80.30553,
"…": "(8 more fields)"
}
] Field Reference
a Semi-major axis of the orbit in astronomical units (AU). e Orbital eccentricity — 0 is a perfect circle, closer to 1 means more elliptical. H Absolute magnitude, used to estimate the size of the object. Implementation Example
Calls a real endpoint of this API. Replace any placeholder credentials with your own key.
const url = "http://www.asterank.com/api/mpc?query={%22e%22:{%22%24lt%22:0.1}}&limit=5";
const response = await fetch(url);
if (!response.ok) throw new Error(`Request failed: ${response.status}`);
const data = await response.json();
console.log(data); What Can You Build?
Note: These code examples are AI-generated and unverified. Always refer to the official API documentation for accurate usage.
How This API Fails
We deliberately sent this API a broken request and recorded exactly what came back on 2026-08-10. Knowing the shape of an error before you hit it makes error handling much easier to write.
Returned an HTML error page rather than JSON — worth knowing if your client assumes every response can be parsed as JSON.
{
"error": "bad request"
} Common Errors & Troubleshooting
Generated guidance based on this API's documentation, not observed by us. Treat it as a starting point and check against the provider's own error reference.
Measured Score Breakdown
Live HTTP request to the API endpoint
Fully tested on Aug 10, 2026
Technical Specifications
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