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 API contracts indexed 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.

The Astronomy API catalog on APIs.io includes 1 Spectral governance ruleset.

Astronomy API’s developer surface includes engineering blog, authentication, developer portal, documentation, signup flow, changelog, support, and 22 more developer resources.

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39.0/100 thin ▬ flat Agent 28/100 agent aware Front door AI 1/6 silent Heartbeat 86/100 alive saas Full breakdown ↓
scored 2026-11-06 · rubric v0.27.0 · Show this score on your site →

AccessPaid

2 published contracts 4 Agent Skills 5 Features 3 Use Cases

AstronomyCelestial DataSpaceMoon PhasesStar Charts

Kin Score

Kin Score How this is scored →
scored 2026-11-06 · rubric v0.27.0

Composite quality — 39.0/100 · thin

Contract Quality 8.8 / 19

Developer Ergonomics 9.9 / 15

Access Clarity 2.0 / 15

Operational Transparency 1.8 / 10

Contract Governance 1.6 / 9

Discoverability 5.5 / 8

Regulatory Posture 2.5 / 15

Create-or-Update Ergonomics 0.0 / 10

Agent readiness — 28/100 · 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

Pagination 5 / 5

Distinct Operations 3 / 3

MCP Tool Quality 6 / 6

Regulatory Posture applies to this provider. Its tags matched the Horizontal (data, software, accessibility, platform) regime, so Regulatory Posture carries 15 points of the composite. If this regime is wrong for your business, say so on your provider repo — the applicability map is public and we will correct it.

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.

The six quality facets above are damped to 75 points between them, because the conditional facet above carries the other 25. That is why each facet's contribution is shown against a damped maximum: raising a quality facet moves the composite by 75% of its nominal weight, not 100%. The full arithmetic is at apis.io/rating/.

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Agent readiness — checks not met, largest first (exact, from this profile):

MCP Server +12 pts — deployment.mode + probe verdict on the mcp/ manifest, not the pointer; an unprobed slug falls back to authorship
Idempotency +9 pts — OpenAPI mutating operations declare an idempotency key — a header, a request-body property, or a named de-duplication token whose own description says so (verified); else common[].type matches /idempoten/i (documented)
A2A Agent Card +8 pts — a2a/-a2a.yml manifest, graded on conformance.grade against A2A 1.0.0
Registration Without a Human +6 pts — a `registration_endpoint` in the served RFC 8414 / OIDC discovery document
Delegated User Identity +6 pts — a served discovery document listing authorization_code in grant_types_supported (served), else an oauth2 authorizationCode flow or openIdConnect declared in an OpenAPI (documented)
Typed Event Surface +6 pts — AsyncAPI document, OR webhooks/callbacks objects in the as-published OpenAPI, OR common[].type includes Webhooks

6 more unmet checks in the Agent Readiness table above.

Kin Score — facets with the most composite points still available (weight × headroom):

Access Clarity scores 13.2 — up to +17.4 composite points
Contract Quality scores 47.0 — up to +13.3 composite points
Operational Transparency scores 18.4 — up to +10.6 composite points

Each check links to what satisfies it. Publish the artifact, or tell us where it already lives, and the score moves on the next scoring run.

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 the provider profile at artifacts.apis.io/astronomy-api/apis.yml: open an issue on github.com/api-evangelist/astronomy-api to ask a question or point us at an artifact you publish. Submit an artifact on GitHub — free → Manage your own listing — the Influence plan, $499/mo →

Markets this provider is in provisional

The Kin Score Market layer reads a provider inside its market: its position, and how deep its integrations go. Depth is only comparable within a position. Provisional and unweighted: not part of the Kin Score or agent readiness.

Market	Position	Depth	Registered MCP server	Declares compatibility
Space and Satellite (operators, earth observation, ground segment)	undeclared	-	-	-

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.

Spectral Rules 1

Spectral governance rulesets for linting and validating these APIs.

Astronomy API API Rules

56 rules · 52 errors 2 warnings 2 info

SPECTRAL

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 4

Pricing, plans, and the legal terms of use

Plans

FinOps

Terms of Service

Privacy Policy

Company 2

The organization behind the API

Blog

Blog

Website

Website

Other 1

Properties that don't map to a standard resource type

Overlay

Overlay

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: paid
  onboarding: unknown
  trial: false
  try_now: false
  public: false
  label: Paid
  confidence: high
  source:
  - finops
  - authentication
  - rate-limits
  - security
  generated: '2026-11-06'
  method: derived
image: https://kinlane-images.s3.amazonaws.com/shared/apis-json/icons/astronomy-api.png
x-docs-platform: gitbook
x-docs-platform-confidence: high
x-docs-platform-checked: 2026-09-19
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: '2026-10-06'
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
common:
- type: Plans
  url: plans/astronomy-api-plans-pricing.yml
- type: FinOps
  url: finops/astronomy-api-finops.yml
- url: https://astronomyapi.com/blog/
  type: Blog
- type: Overlay
  url: overlays/astronomy-api-v3-overlay.yaml
- 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

Astronomy API — frequently asked questions

Does Astronomy API have an API?

Yes. APIs.io lists 5 APIs from Astronomy API, including Astronomy API, Astronomy API Bodies API and Astronomy API Events API, and 2 more.

Is there an OpenAPI specification for the Astronomy API?

Yes. APIs.io indexes 4 OpenAPI specifications for Astronomy API, each linked for download from this page.

How do I authenticate with the Astronomy API?

Astronomy API uses bearer-token authentication (http · 2 schemes). The details are profiled on APIs.io as Astronomy Api Authentication.

Is the Astronomy API ready for AI agents?

Astronomy API has a Kin Score of 39.0 out of 100 (thin) and an Agent Readiness score of 28.4 (agent-aware), scored by API Evangelist on 2026-11-06.

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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.
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