M
API Matrix

arcsecond.io API

⭐ Beginner's Pick Science & Math / No Auth Required Beginner HTTPS
Free to Use Varies (check documentation)
82 Score
Grade A
Visit Official Site Compare Alternatives

Overview

arcsecond.io is a free astronomy API that aggregates data from multiple space databases, including stars, planets, exoplanets, and observing sites. You can query celestial objects by name or coordinates and get rich scientific data back. No API key is required, making it perfect for beginners wanting to explore astronomy data.

💡

Beginner Tip

Try querying a well-known object like "Mars" or "Sirius" first to see the data structure before building more complex queries. The API returns JSON that is easy to parse in any language.

Available Data

Use case: Integrate multiple astronomy data sources data into web and mobile applications
arcsecond.io data via REST API
JSON-formatted response data
Freely accessible without authentication

Example Response

JSON Response 
{
  "title": "Astronomy Picture of the Day",
  "date": "2025-01-15",
  "explanation": "A stunning nebula captured by the James Webb Telescope...",
  "url": "https://apod.nasa.gov/apod/image/...",
  "media_type": "image"
}

Field Reference

name Common or catalogue name of the celestial object.
right_ascension Right ascension coordinate in degrees.
declination Declination coordinate in degrees.
object_types List of classifications for the object (e.g., star, planet, galaxy).
aliases Alternative names or catalogue designations for the object.

Implementation Example 

const url = "https://api.arcsecond.io/";
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.

Common Errors & Troubleshooting

404 Not Found The object name was misspelled or is not in the database.
✓ Try alternate names or spellings (e.g., "alpha-centauri" instead of "Alpha Centauri").
Empty results array The search query did not match any catalogued objects.
✓ Broaden your search term or use a standard astronomical designation like an HD or NGC number.
CORS error in browser Direct browser requests to the API may be blocked depending on origin.
✓ Proxy the request through your backend server to avoid CORS issues.

Matrix Score Breakdown

🌐 Reachability 30/30
⚡ Speed 15/20
🔒 Security 15/15
🛠 Developer XP 15/20
✓ Reliability 7/15
Response Time 226ms

Fully tested on Apr 5, 2026

Technical Specifications

Auth No Auth
HTTPS REQUIRED
CORS UNKNOWN
Category Science & Math
Difficulty Beginner
Verified: 2026-04-04

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