API · /deepsky-api

Deep-Sky Objects API

healthy 3,336 Subscribers

The OpenNGC (NGC/IC) catalogue of deep-sky objects as an API — 13,000+ galaxies, nebulae and star clusters. Look up any object by its catalogue name (NGC224, IC434), Messier number (M31 → Andromeda Galaxy, M42 → Orion Nebula, M1 → Crab Nebula) or common name; browse the full 110-object Messier catalogue; or search by type (galaxy, planetary nebula, globular cluster…) and constellation. Each record carries the object type, J2000 coordinates (sexagesimal + decimal), V/B magnitude, angular size, surface brightness, Hubble morphological type, constellation and cross-catalogue identifiers. Ideal for astronomy apps, telescope planners, planetarium software and education.

#deep-sky #ngc #messier #galaxies #nebulae #astronomy

api.oanor.com/deepsky-api

Get an API key Try in playground → Contact provider

Machine-readable spec so AI agents can integrate this API.

/api/deepsky-api/openapi.json

/api/deepsky-api/llms.txt

Discovery: GET /api/index.json lists every API.

Deep-Sky Objects API — live data on the oanor API marketplace

API health

healthy

Uptime: 100.00%; Server probes · 24h
Avg latency: 79 ms; Server probes · 24h
Subscribers: 3,336; active
Total calls: 76; last 7 days

Full status page → · 8 probes/24h

Pricing

Pick a tier — billed monthly, cancel anytime.

Free

4,000 calls / month
2 requests / second
Hard cap (429 above quota, no overage)
4,000 calls/month
2 req/sec
Object + Messier + search
No credit card

Starter

€5.50 /month

50,000 calls / month
8 requests / second
Hard cap (429 above quota, no overage)
50k calls/month
8 req/sec
Type / constellation filters
Email support

Pro

€17.50 /month

260,000 calls / month
20 requests / second
Hard cap (429 above quota, no overage)
260k calls/month
20 req/sec
Planetarium / planners
Priority support

Mega

€45.00 /month

1,250,000 calls / month
50 requests / second
Hard cap (429 above quota, no overage)
1.25M calls/month
50 req/sec
Astronomy platform
Dedicated SLA

Built by

PremiumApi

Related APIs

Other APIs with overlapping tags.

Meteorites API

NASA's catalogue of 45,000+ meteorites recovered on Earth as an API. For each meteorite: its name, NASA id, classification (recclass, e.g. L5, Iron), mass in grams, whether it was seen to fall or simply found, the year, and the latitude/longitude where it was recovered. Look one up by name or id, find the meteorites NEAR any coordinate (great-circle distance), rank by mass or year, list a classification or year, or search. Great for space, education, mapping and museum apps. Distinct from asteroids and close-approach data — these are rocks already on the ground.

api.oanor.com/meteorites-api

Constellations API

The 88 modern IAU constellations as an API — the reference an astronomy app, planetarium or education tool needs. For each constellation: its official IAU abbreviation, English name, the Latin genitive used when naming stars (e.g. "Alpha Andromedae"), a size rank, the approximate centre in equatorial coordinates (right ascension / declination) and the constellation name in roughly 25 languages. Look one up by abbreviation or name, search across every language, find which constellation a sky position falls nearest to, or list them all. Distinct from stars-api (individual stars) — this is the reference for the constellations themselves. Served from memory — always fast.

api.oanor.com/constellations-api

Observatory Codes API

The IAU Minor Planet Center list of observatory codes as an API — every site the MPC uses to identify a telescope when it publishes astrometric observations of asteroids and comets. For each of 2,700+ codes: the 3-character code, the observatory name, its east longitude and the parallax constants (rho·cos φ', rho·sin φ'). From those constants the API derives each site's geocentric latitude and a -180..180 longitude, so you can find the observatories nearest any point on Earth with a great-circle (haversine) search. Look one up by code, search by name, list them all, or find the closest sites to a latitude/longitude. Distinct from telescope-api (optics maths) — this is the registry of real observing sites and where they are. Served from memory — always fast.

api.oanor.com/observatories-api

Sundial API

Sundial gnomonics maths as an API, computed locally and deterministically — the hour-line, gnomon and longitude-correction numbers a dial maker, horologist or astronomy hobbyist lays a sundial out with. The hour-line-angle endpoint gives the angle of each hour line on the dial plate, measured from the noon line: for a horizontal dial tan(angle) = sin(latitude) × tan(hour angle), and for a vertical south-facing dial cos(latitude) is used instead, where the hour angle is 15° per hour from solar noon. At 50° latitude the 1-o'clock line sits about 11.6° from noon rather than 15° — the lines bunch near noon and spread toward the ends, which is exactly why a sundial's hours are unevenly spaced. The gnomon endpoint gives the style angle: the gnomon's shadow-casting edge must point at the celestial pole, so it rises at the latitude angle on a horizontal dial (50° at 50° N) and at 90° − latitude on a vertical dial — get this wrong and the dial keeps correct time at only one season. The longitude-correction endpoint converts the dial's local apparent time to clock time: 4 minutes of time per degree of longitude, correction = 4 × (reference meridian − local longitude), so a dial at 7.5° E on Central European Time reads 30 minutes slow versus the clock. Everything is computed locally and deterministically, so it is instant and private. Ideal for sundial-design and gnomonics tools, astronomy-education and maker apps, and horology calculators. Pure local computation — no key, no third-party service, instant. Add the equation of time for full clock accuracy. 3 compute endpoints. For the sun's position use a solar-position API; for sunrise and sunset a sunrise API.

api.oanor.com/sundial-api

Frequently asked questions

Quick answers about pricing, quotas, and integration.

How do I get an API key for Deep-Sky Objects API?

Sign up for free at oanor.com, generate an API key from the developer dashboard, and call Deep-Sky Objects API with the x-oanor-key header. No credit card needed for the free tier.

What's the rate limit for Deep-Sky Objects API?

Free tier allows 1 request per second. Paid plans scale up to 50 requests per second on the Mega tier. Hard limits return HTTP 429 above the quota — no surprise overage charges.

How much does Deep-Sky Objects API cost?

Deep-Sky Objects API has a free tier with 100 calls / month. Paid plans start at €5.50 / month with higher quotas and faster rate limits.

Can I cancel my subscription anytime?

Yes. Plans are billed monthly and you can cancel anytime from your billing dashboard. No long-term contracts and no cancellation fee.

Is Deep-Sky Objects API GDPR-compliant?

All requests to Deep-Sky Objects API go through our EU-based gateway. Your upstream API key never leaves our server and no personal data is shared with the upstream provider beyond the request you send.

Deep-Sky 3

Meta 1

Pick an endpoint from the list on the left to see its details and try it.

GET /v1/messier

A Messier object, or the full Messier catalogue

Playground

Parameters

Custom headers

Language: Client:

GET /v1/object

An object by catalogue name, Messier number or common name

Playground

Parameters

Custom headers

Language: Client:

GET /v1/search

Search by name/common name with type & constellation filters

Playground

Parameters

Custom headers

Language: Client:

GET /v1/meta

Totals & object-type breakdown

Playground

Custom headers

Language: Client:

Code snippets

curl https://api.oanor.com/deepsky-api/SOME_PATH \
  -H "x-oanor-key: oanor_test_..."

const res = await fetch("https://api.oanor.com/deepsky-api/SOME_PATH", {
  headers: { "x-oanor-key": "oanor_test_..." }
});
const data = await res.json();

$ch = curl_init("https://api.oanor.com/deepsky-api/SOME_PATH");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-oanor-key: oanor_test_..."]);
$response = curl_exec($ch);

import requests
r = requests.get(
    "https://api.oanor.com/deepsky-api/SOME_PATH",
    headers={"x-oanor-key": "oanor_test_..."},
)
print(r.json())

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Deep-Sky Objects API

API health

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Related APIs

Meteorites API

Constellations API

Observatory Codes API

Sundial API

Frequently asked questions

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