A secure, React-free Electron desktop application for exploring astronomy data and planning observations. Built with vanilla JavaScript, HTML, and CSS — plus a static browser build that runs the same UI without Electron.

Live demo: https://guildmasterdev.github.io/Astronomer/

• NASA APOD: Browse Astronomy Picture of the Day with date picker and random selection
• Image & Video Library: Search NASA's extensive media collection
• EPIC Earth Images: View recent natural color images of Earth from space
• ISS Tracker: Real-time International Space Station position and pass predictions

• Discover what Hubble saw on your birthday
• Browse through years of Hubble observations
• Smart date matching with ±3 day tolerance

• Location-based observation planning (manual or GPS)
• Twilight times (civil, nautical, astronomical)
• Moon phase and illumination calculations
• Planet visibility predictions
• ISS pass predictions for your location

• Solar System object catalog with real-time data
• Notable exoplanet database
• Distance calculations and tracking
• Quick facts and observation windows

• Save any image, object, or observation
• Export favorites as JSON
• Share functionality with system integration

• NASA API key configuration
• Dark/Light theme switching
• Metric/Imperial units
• Location defaults
• Performance modes and caching

The live demo at https://guildmasterdev.github.io/Astronomer/ runs the same UI directly in the browser — no download required. A few notes:

• It defaults to NASA's shared DEMO_KEY, which has tight hourly rate limits. A one-minute signup at https://api.nasa.gov/ yields a free personal key; drop it into Settings → NASA API Key and the demo-mode banner disappears.
• Favorites and settings persist to localStorage, so they stay on the device you used.
• Everything astronomical — twilight, moon phase, planet positions, ISS passes — runs client-side via astronomy-engine and satellite.js.
• Location can come from the browser's Geolocation API (you'll be prompted) or from a manual entry.

The desktop build remains the better option for heavy usage (no CORS constraints, persistent encrypted store, native dialogs).

• Context Isolation: Enabled by default
• Sandbox Mode: All renderer processes sandboxed
• CSP Headers: Strict Content Security Policy
• API Whitelisting: Only approved endpoints accessible
• Rate Limiting: Built-in request throttling
• No Remote Code: No external script execution

• Node.js 20+
• npm
• NASA API Key (optional, uses DEMO_KEY by default — configure in the in-app Settings)

# Clone the repository
git clone https://github.com/guildmasterdev/Astronomer.git
cd Astronomer

# Install dependencies
npm install

# Run the desktop app
npm run dev

1. Visit api.nasa.gov
2. Register for a free API key
3. Add it in Settings → NASA API Key (desktop or web)

# Desktop production build (TypeScript + Vite renderer)
npm run build

# Package desktop app for a specific platform
npm run pack:mac
npm run pack:win
npm run pack:linux

# Static web build (output: dist-web/)
npm run build:web
npm run preview:web   # local preview

Astronomer/
├── src/
│   ├── main/           # Electron main process
│   │   ├── main.ts     # App entry point, BrowserWindow + CSP
│   │   ├── menu.ts     # Application menu
│   │   ├── store.ts    # Persistent storage (electron-store)
│   │   ├── ipc.ts      # IPC handlers
│   │   ├── endpoints.ts # API whitelist
│   │   ├── astronomy.ts # Sun/moon/planet compute
│   │   ├── iss.ts      # TLE + SGP4 pass prediction
│   │   └── rate-limiter.ts
│   ├── preload/        # Secure context bridge
│   │   └── preload-simple.js
│   ├── renderer/       # UI (vanilla JS, shared by desktop + web)
│   │   ├── index.html
│   │   ├── styles.css
│   │   ├── app-complete.js   # application logic
│   │   └── public/vendor/    # bundled Leaflet
│   └── web/            # Static browser build
│       ├── index.html  # web shell with demo banner
│       ├── main.js     # window.astronomer shim + loader
│       └── prepare.mjs # stages shared renderer assets
├── dist/               # Compiled desktop output
├── dist-web/           # Compiled web output
└── dist-electron/      # Packaged installers

npm run dev        # Compiles TS then launches Electron
npm run dev:vite   # Vite-hosted renderer (for live reload)
npm run build:web  # Static web build
npm test           # vitest
npm run test:e2e   # playwright
npm run lint       # ESLint 9 (flat config)
npm run typecheck  # tsc --noEmit

The app uses these NASA and astronomy APIs (whitelisted in both the desktop CSP and the web fetch adapter):

• NASA APOD API
• NASA Image and Video Library
• NASA EPIC API
• JPL Horizons API
• ISS Location API (wheretheiss.at)
• ISS TLE (tle.ivanstanojevic.me)
• NASA Exoplanet Archive

• No tracking: Zero telemetry by default
• Local storage: All data stored locally (electron-store on desktop, localStorage in the web demo)
• No accounts: No user accounts or cloud sync
• Whitelisted APIs: Desktop builds route every external call through a validated allow-list; CSP blocks everything else
• Open source: Full code transparency

Contributions are welcome! Please read our contributing guidelines before submitting PRs.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

MIT License — see LICENSE file for details.

• NASA APIs for providing amazing space data
• astronomy-engine for celestial calculations
• satellite.js for SGP4/SDP4 propagation
• Electron team for the framework
• All contributors and testers

• Report issues: GitHub Issues
• Documentation: Wiki

Built with ❤️ for space enthusiasts everywhere