Astronomy API

AstronomyAPI is a web API for retrieving astronomical information including data about celestial bodies, moon phases, planet positions, star charts, and astronomical events for a given location and time. The API provides developers with access to celestial body positions, astronomical event data, star chart generation, moon phase imagery, and deep space object search capabilities for any geographic location and date/time combination.

Astronomy API publishes 5 APIs on the APIs.io network, including Bodies API, Events API, Search API, and 2 more. Tagged areas include Astronomy, Celestial Data, Space, Moon Phases, and Star Charts.

Astronomy API’s developer surface includes authentication, developer portal, documentation, signup flow, changelog, support, and 19 more developer resources.

🌐 Visit website 📡 Source on GitHub

39.3/100 developing ▬ flat Agent 26/100 agent aware saas Full breakdown ↓
scored 2026-09-08 · rubric v0.20.0

AccessFreemiumSelf serve⚡ Free to try

1 APIs 5 Features 3 Use Cases

AstronomyCelestial DataSpaceMoon PhasesStar Charts

Kin Score

Kin Score How this is scored →
scored 2026-09-08 · rubric v0.20.0

Composite quality — 39.3/100 · developing

Contract Quality 11.3 / 23

Developer Ergonomics 11.5 / 18

Access Clarity 3.8 / 18

Operational Transparency 2.2 / 12

Contract Governance 0.5 / 11

Discoverability 6.8 / 9

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 26/100 · agent aware

Machine-Readable Contract 18 / 18

Agentic Access Contract 10 / 10

Documented Reversibility 0 / 6

MCP Server 0 / 12

Machine-Readable Auth 10 / 10

Idempotency 0 / 9

Stable Error Semantics 8 / 8

Request/Response Examples 7 / 7

Rate-Limit Signaling 7 / 7

Typed Event Surface 0 / 6

Agent Skills 5 / 5

Well-Known Catalog 0 / 4

Consent & Bot Identity 0 / 3

A2A Agent Card 0 / 8

Dry-Run / Simulate Mode 0 / 4

Delegated User Identity 0 / 6

Protected Resource Metadata 0 / 5

Registration Without a Human 0 / 6

Agentic Commerce Well-Known Document 0 / 5

Create-or-Update Ergonomics applies to this provider. This API accepts writes, so it carries 10 points of the composite. It is scored from the published contracts themselves: whether a caller can create-or-update in one call, whether the write accepts a key the caller already holds, and whether the response says which branch ran. Without that, every write needs a search-and-branch in front of it, and the first time that check is skipped a duplicate record is created. Scored against the observed mean rather than raw — a provider at the catalog average is unchanged by this facet, not penalised by it.

Improve this rating by publishing the missing artifacts — every area above can be raised, and the full rubric is at apis.io/rating/. Every facet and dimension name above is a link: it opens that measurement's own page — what it means, the exact checks that feed it, how the whole catalog distributes on it, and the providers at the top of it. This rating is computed from github.com/api-evangelist/astronomy-api: open an issue to ask a question, or submit a pull request to add artifacts. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

APIs 6

Individual APIs this provider publishes, each with its own machine-readable definition.

Astronomy API

The Astronomy API provides access to astronomical data including celestial body positions, moon phases, planet positions, star charts, astronomical events, and deep space object...

Astronomy API Bodies API

Celestial body information and positions

Astronomy API Events API

Astronomical events for a given location and date range

Astronomy API Search API

Search for stars and deep space objects

Astronomy API Studio API

Generated imagery (moon phase and star charts)

Astronomy API v3

Version 3 of the Astronomy API, published by the provider as a reference draft with a complete OpenAPI 3.1 definition before it ships — "so that the design can be read and argue...

Open Collections 6

Open, tool-agnostic API collections (OpenAPI-derived and Bruno).

API Collection

OPEN COLLECTION

Astronomy Bodies API

OPEN COLLECTION

Astronomy Bodies Events API

OPEN COLLECTION

Astronomy Bodies Search API

OPEN COLLECTION

Astronomy Bodies Studio API

OPEN COLLECTION

Astronomy API

OPEN COLLECTION

Pricing Plans 1

Published pricing tiers and plan structures.

Astronomy Api Plans Pricing

0 plans

PLANS

Rate Limits 1

Documented rate limits and quota policies.

Astronomy Api Rate Limits

0 limits

RATE LIMITS

FinOps 1

Cost, billing, and metering signals for API financial operations.

Astronomy Api Finops

FINOPS

Features 5

Notable capabilities this provider offers.

Celestial Body Positions

Retrieve real-time and historical positions of celestial bodies including planets, moons, and other astronomical objects for any geographic location and date/time.

Astronomical Events

Access data on celestial events such as eclipses, conjunctions, and other notable astronomical occurrences for a given body and date range.

Star Chart Generation

Generate customizable star charts as images for any sky position, date, and observer location for use in applications and publications.

Moon Phase Imagery

Generate moon phase images showing the illumination and appearance of the moon for any given date and location.

Deep Space Object Search

Search for stars and deep space objects by name or catalog designation to retrieve positional and descriptive data.

Security Posture 2

Authentication, domain security, vulnerability disclosure, and trust-center signals.

Astronomy Api Authentication

http · 2 schemes

SECURITY

Astronomy Api Domain Security

TLSv1.3 · HSTS

SECURITY

Agentic Access 1

Recommended x-agentic-access execution contracts for AI agents.

Astronomy Api Agentic Access

7 operations · 2 acting

AGENTIC

Use Cases 3

What developers build with this provider.

Astronomy Education Apps

Developers build educational astronomy applications that display real-time planet positions, star charts, and moon phases for learners and enthusiasts.

Observation Planning Tools

Amateur astronomers use the API to plan observing sessions by retrieving celestial body positions and upcoming astronomical events for their location.

Astrology and Horoscope Applications

Astrology apps integrate the Astronomy API for accurate planetary position data to power birth chart calculations and transit predictions.

Integrations 2

Pre-built integrations with other platforms and tools.

Mobile Astronomy Apps

Mobile applications integrate the Astronomy API to provide real-time sky data and star chart overlays for stargazing experiences.

Planetarium Software

Planetarium and sky simulation software integrates celestial body position data from the Astronomy API for accurate sky rendering.

Resources

Get Started 2

Portal, sign-up, and the first successful call

Astronomy API Website

Portal

Sign Up

Signup

Documentation 1

Reference material describing how the API behaves

Documentation

Documentation

Agent Surfaces 4

MCP servers, agent skills, and machine-readable catalogs

AgenticAccess

AgenticAccess

llms.txt (documentation host)

LlmsText

X-MCPServerCandidate

X-MCPServerCandidate

AgentSkill

AgentSkill

Design & Contract 6

Pagination, idempotency, versioning, errors, and events

Conventions

ErrorCatalog

Lifecycle

Conformance

DataModel

Components

Build 4

SDKs, sample code, and the tooling you integrate with

GitHubOrganization

Packages

SDKs

ToolCrosswalk

Access & Security 2

Authentication, authorization, and security posture

DomainSecurity

DomainSecurity

Authentication

Authentication

Operate 3

Status, limits, changes, and where to get help

Changelog

ChangeLog

Support (GitHub issues, per the provider's Getting Started page)

Support

RateLimits

RateLimits

Commercial 2

Pricing, plans, and the legal terms of use

Terms of Service

TermsOfService

Privacy Policy

PrivacyPolicy

Company 1

The organization behind the API

Website

Website

Source (apis.yml)

aid: astronomy-api
name: Astronomy API
description: AstronomyAPI is a web API for retrieving astronomical information including data about celestial bodies, moon
  phases, planet positions, star charts, and astronomical events for a given location and time. The API provides developers
  with access to celestial body positions, astronomical event data, star chart generation, moon phase imagery, and deep space
  object search capabilities for any geographic location and date/time combination.
type: Index
deliveryModel:
  model: saas
  open_source: false
  commercial: true
  callable_host: true
  label: Hosted service · you call their endpoint
  confidence: high
  source:
  - openapi
  - pricing
  generated: '2026-08-28'
  method: derived
accessModel:
  pricing: freemium
  onboarding: self-serve
  trial: false
  try_now: true
  public: false
  label: Freemium · Self-serve signup
  confidence: medium
  source:
  - plans
  - authentication
  - security
  generated: '2026-09-03'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/astronomy-api.png
tags:
- Astronomy
- Celestial Data
- Space
- Moon Phases
- Star Charts
url: https://raw.githubusercontent.com/api-evangelist/astronomy-api/refs/heads/main/apis.yml
created: '2024-03-30'
modified: '2026-09-04'
specificationVersion: '0.23'
apis:
- aid: astronomy-api:astronomy-api
  name: Astronomy API
  description: The Astronomy API provides access to astronomical data including celestial body positions, moon phases, planet
    positions, star charts, astronomical events, and deep space object search for any location and time. Endpoints cover bodies,
    positions, events, studio image generation, star charts, moon phase imagery, and search for stars and deep space objects.
  humanURL: https://docs.astronomyapi.com/
  baseURL: https://api.astronomyapi.com/api/v2
  tags:
  - Astronomy
  - Moon
  - Planets
  - Star Charts
  properties:
  - type: Documentation
    url: https://docs.astronomyapi.com/
  - type: GettingStarted
    url: https://docs.astronomyapi.com/
    title: Getting Started
  - type: APIReference
    url: https://docs.astronomyapi.com/endpoints/bodies
    title: Endpoint reference
- aid: astronomy-api:astronomy-api-bodies-api
  name: Astronomy API Bodies API
  description: Celestial body information and positions
  humanURL: https://docs.astronomyapi.com/
  baseURL: https://api.astronomyapi.com/api/v2
  tags:
  - Bodies
  properties:
  - type: OpenAPI
    url: openapi/astronomy-api-bodies-api-openapi.yml
  - type: Overlay
    url: overlays/astronomy-api-bodies-api-overlay.yaml
- aid: astronomy-api:astronomy-api-events-api
  name: Astronomy API Events API
  description: Astronomical events for a given location and date range
  humanURL: https://docs.astronomyapi.com/
  baseURL: https://api.astronomyapi.com/api/v2
  tags:
  - Event
  tags_raw:
  - Events
  properties:
  - type: OpenAPI
    url: openapi/astronomy-api-events-api-openapi.yml
  - type: Overlay
    url: overlays/astronomy-api-events-api-overlay.yaml
- aid: astronomy-api:astronomy-api-search-api
  name: Astronomy API Search API
  description: Search for stars and deep space objects
  humanURL: https://docs.astronomyapi.com/
  baseURL: https://api.astronomyapi.com/api/v2
  tags:
  - Search
  properties:
  - type: OpenAPI
    url: openapi/astronomy-api-search-api-openapi.yml
  - type: Overlay
    url: overlays/astronomy-api-search-api-overlay.yaml
- aid: astronomy-api:astronomy-api-studio-api
  name: Astronomy API Studio API
  description: Generated imagery (moon phase and star charts)
  humanURL: https://docs.astronomyapi.com/
  baseURL: https://api.astronomyapi.com/api/v2
  tags:
  - Studio
  properties:
  - type: OpenAPI
    url: openapi/astronomy-api-studio-api-openapi.yml
  - type: Overlay
    url: overlays/astronomy-api-studio-api-overlay.yaml
- aid: astronomy-api:astronomy-api-v3
  name: Astronomy API v3
  description: 'Version 3 of the Astronomy API, published by the provider as a reference draft with a complete OpenAPI 3.1
    definition before it ships — "so that the design can be read and argued with". A breaking redesign of the v2 request and
    response shapes: JSON numbers instead of strings, one representation per value, a declared meta.units block, ISO 8601
    instants with an explicit sampling step and timezone, cursor pagination on positions, RFC 9457 problem details, bearer
    authentication, and apsis events alongside eclipses. Five operations across positions, events, search and the two studio
    renderers. NOT YET IN PRODUCTION — /api/v2 remains the callable surface.'
  humanURL: https://docs.astronomyapi.com/api-v3-reference-draft/v3
  baseURL: https://api.astronomyapi.com/api/v3
  tags:
  - Astronomy
  - Positions
  - Events
  - Star Charts
  properties:
  - type: OpenAPI
    url: openapi/astronomy-api-v3-openapi.yaml
  - type: Overlay
    url: overlays/astronomy-api-v3-overlay.yaml
  - type: Documentation
    url: https://docs.astronomyapi.com/api-v3-reference-draft/v3
    title: v3 reference draft
  - type: Documentation
    url: https://docs.astronomyapi.com/api-v3-reference-draft/v3/migrating-from-v2
    title: Migrating from v2
common:
- type: Website
  url: https://astronomyapi.com/
- type: AgenticAccess
  url: agentic-access/astronomy-api-agentic-access.yml
- type: DomainSecurity
  url: security/astronomy-api-domain-security.yml
- type: Authentication
  url: authentication/astronomy-api-authentication.yml
- type: GitHubOrganization
  url: https://github.com/AstronomyAPI
- type: Portal
  url: https://astronomyapi.com/
  title: Astronomy API Website
- type: Documentation
  url: https://docs.astronomyapi.com/
  title: Documentation
- type: Signup
  url: https://astronomyapi.com/auth/signup
  title: Sign Up
- type: Features
  data:
  - name: Celestial Body Positions
    description: Retrieve real-time and historical positions of celestial bodies including planets, moons, and other astronomical
      objects for any geographic location and date/time.
  - name: Astronomical Events
    description: Access data on celestial events such as eclipses, conjunctions, and other notable astronomical occurrences
      for a given body and date range.
  - name: Star Chart Generation
    description: Generate customizable star charts as images for any sky position, date, and observer location for use in
      applications and publications.
  - name: Moon Phase Imagery
    description: Generate moon phase images showing the illumination and appearance of the moon for any given date and location.
  - name: Deep Space Object Search
    description: Search for stars and deep space objects by name or catalog designation to retrieve positional and descriptive
      data.
- type: UseCases
  data:
  - name: Astronomy Education Apps
    description: Developers build educational astronomy applications that display real-time planet positions, star charts,
      and moon phases for learners and enthusiasts.
  - name: Observation Planning Tools
    description: Amateur astronomers use the API to plan observing sessions by retrieving celestial body positions and upcoming
      astronomical events for their location.
  - name: Astrology and Horoscope Applications
    description: Astrology apps integrate the Astronomy API for accurate planetary position data to power birth chart calculations
      and transit predictions.
- type: Integrations
  data:
  - name: Mobile Astronomy Apps
    description: Mobile applications integrate the Astronomy API to provide real-time sky data and star chart overlays for
      stargazing experiences.
  - name: Planetarium Software
    description: Planetarium and sky simulation software integrates celestial body position data from the Astronomy API for
      accurate sky rendering.
- type: LlmsText
  url: https://docs.astronomyapi.com/llms.txt
  title: llms.txt (documentation host)
- type: ChangeLog
  url: https://docs.astronomyapi.com/changelog
  title: Changelog
- type: TermsOfService
  url: https://astronomyapi.com/terms-of-service
  title: Terms of Service
- type: PrivacyPolicy
  url: https://astronomyapi.com/privacy-policy
  title: Privacy Policy
- type: Support
  url: https://github.com/AstronomyAPI/Samples/issues
  title: Support (GitHub issues, per the provider's Getting Started page)
- type: Conventions
  url: conventions/astronomy-api-conventions.yml
- type: ErrorCatalog
  url: errors/astronomy-api-problem-types.yml
- type: Lifecycle
  url: lifecycle/astronomy-api-lifecycle.yml
- type: Conformance
  url: conformance/astronomy-api-conformance.yml
- type: DataModel
  url: data-model/astronomy-api-data-model.yml
- type: Packages
  url: packages/astronomy-api-packages.yml
- type: SDKs
  url: packages/astronomy-api-packages.yml
- type: Components
  url: components/astronomy-api-components.yml
- type: RateLimits
  url: rate-limits/astronomy-api-rate-limits.yml
- type: ToolCrosswalk
  url: mcp/astronomy-api-tool-crosswalk.yml
- type: X-MCPServerCandidate
  url: mcp/astronomy-api-mcp.yml
- type: AgentSkill
  url: skills/_index.yml
x-enrichment:
  date: '2026-09-04'
  status: enriched
  artifacts_added: 23
  pass: local-v3
maintainers:
- FN: Kin Lane
  email: kin@apievangelist.com

Work with this as data

Every provider here is available over the APIs.io API and to AI agents over MCP.

MCP server

One button, every client — Claude, Cursor, VS Code and the rest.

https://apis.io/mcp

Tools for providers

9 MCP tools reach this

find_providersBrowse and filter every provider in the catalog.
get_provider_artifactsEvery artifact this provider publishes, grouped by type.
get_provider_operationsEvery operation across all of their OpenAPIs — one call instead of parsing every spec.
get_provider_toolsEvery MCP tool they ship, with the operation each wraps.
get_provider_evidenceHow each part of their score was established. Free — the basis for a claim should not sit behind it.
get_provider_ratingPRO — composite, band, trend and facet scores.
apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.
resolveTurn a domain, URL or GitHub org into the provider it belongs to.
find_cohortsEvery scored population of providers in the catalog.

All 92 tools →

Call it yourself

curl for this page

This provider

curl "https://apis.io/api/v1/providers/astronomy-api"

All providers

curl "https://apis.io/api/v1/providers?limit=25"

Every operation they expose

curl "https://apis.io/api/v1/providers/astronomy-api/operations?limit=25"

How their score was established

curl "https://apis.io/api/v1/providers/astronomy-api/evidence"

Discovery needs no key. Ratings and market analysis are Pro.

Get an API key

Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.

GitHub Google LinkedIn

A second provider on the same verified email joins the account you already have.