Star Tracker

A mobile application built with Expo for astronomy enthusiasts to track celestial objects, align telescopes, and enhance stargazing experiences.

Features

Core Functionality

• GPS Location Tracking: Real-time GPS coordinates for accurate positioning
• Compass Integration: Built-in compass for precise directional guidance
• Altitude Monitoring: Altitude details for elevation-based calculations
• Orientation Sensing: Device orientation tracking for alignment purposes

Target Management

• Star Catalog: Access to a comprehensive catalog of celestial targets
• Manual Target Input: Enter custom targets manually for flexibility
• Target List: Browse and select from available astronomical objects
• Target Information: Detailed information cards for selected targets

Telescope Alignment

• Alignment Mode: Step-by-step telescope alignment process
• Alt-Az Guidance: Altitude-Azimuth coordinate system support
• Sensor Overlay: Visual overlays for precise alignment
• Alignment Context: Persistent alignment state management

Observation Tools

• Observe Mode: Dedicated observation interface
• Real-time Tracking: Live updates for moving celestial objects
• Location Status: Current location and sensor status indicators
• Observe Header: Contextual information during observation

User Interface

• Tabbed Navigation: Easy switching between alignment, observation, settings, and targets
• Dark/Light Theme: Adaptive color scheme based on device preferences
• Responsive Design: Optimized for both mobile platforms (iOS/Android)
• Haptic Feedback: Tactile responses for better user interaction

Settings & Customization

• Settings Management: Configurable app preferences
• Theme Customization: Personalize the app appearance
• Sensor Calibration: Fine-tune device sensors for accuracy

Getting Started

Prerequisites

• Node.js
• Expo CLI
• iOS Simulator or Android Emulator (for development)

Installation

1. Install dependencies:

   npm install

2. Start the development server:

   npx expo start

3. Open the app in:

   • Expo Go for quick testing
   • Development build for full functionality
   • iOS Simulator or Android Emulator

Project Structure

• app/: Main application screens and navigation
• components/: Reusable UI components
• context/: React context providers for state management
• hooks/: Custom React hooks
• lib/: Astronomy and orientation calculation utilities
• constants/: App constants and configuration
• assets/: Images and static assets

Technologies Used

• Expo: Cross-platform mobile development framework
• React Native: Mobile UI framework
• TypeScript: Type-safe JavaScript
• React Navigation: Navigation library
• Device Sensors: GPS, compass, and orientation APIs

Screenshots

Coming soon - Screenshots will be added to showcase the app's interface and features.

Technical Details

Astronomy Calculations

The app utilizes astronomical algorithms in lib/astro.ts for:

• Celestial coordinate transformations
• Star position calculations
• Time-based astronomical computations

Sensor Integration

Device sensors are managed through lib/orientation.ts and native Expo APIs for:

• GPS location services
• Magnetometer-based compass
• Accelerometer and gyroscope for orientation
• Altitude measurements

State Management

Context providers handle application state:

• alignment-context.tsx: Telescope alignment state
• settings-context.tsx: User preferences and configuration
• target-context.tsx: Selected celestial targets and catalog data

Build and Deployment

Development Build

npx expo run:ios
npx expo run:android

Production Build with EAS

# Install EAS CLI
npm install -g @expo/eas-cli

# Login to Expo
eas login

# Build for platforms
eas build --platform ios
eas build --platform android

# Submit to stores
eas submit --platform ios
eas submit --platform android

Environment Setup

• Configure app.json and eas.json for build settings
• Set up environment variables in .env files
• Configure app icons and splash screens in assets/

Troubleshooting

Common Issues

GPS/Location Permissions

• Ensure location permissions are granted in device settings
• For iOS: Settings > Privacy & Security > Location Services
• For Android: Settings > Apps > Star Tracker > Permissions

Compass Calibration

• Calibrate device compass by moving in a figure-8 pattern
• Avoid magnetic interference from nearby electronics

Sensor Accuracy

• Ensure device sensors are functioning properly
• Restart the app if sensor readings appear incorrect
• Check for firmware updates on your device

Build Issues

• Clear Expo cache: npx expo start --clear
• Reset project: npm run reset-project
• Check Node.js and Expo versions compatibility

Performance Tips

• Close other apps using GPS/compass sensors
• Use in open areas for better GPS accuracy
• Keep device battery charged for optimal sensor performance

Contributing

Contributions are welcome! Please feel free to submit pull requests or open issues for bugs and feature requests.

Development Setup

1. Fork the repository
2. Clone your fork: git clone https://github.com/yourusername/star-tracker.git
3. Install dependencies: npm install
4. Start development: npx expo start
5. Create a feature branch: git checkout -b feature/your-feature-name
6. Make your changes and test thoroughly
7. Submit a pull request

Code Style

• Follow TypeScript best practices
• Use meaningful variable and function names
• Add comments for complex astronomical calculations
• Test on both iOS and Android platforms

Reporting Issues

When reporting bugs, please include:

• Device model and OS version
• App version
• Steps to reproduce the issue
• Expected vs. actual behavior
• Any relevant error messages or logs

Possible Future Changes

Enhanced Catalog and Search

• Expanded Celestial Catalog: Add more astronomical objects including nebulae, galaxies, planets, and minor planets
• Planetary Support: Include detailed ephemeris data for all planets, dwarf planets, and major planetary moons with accurate position calculations
• Advanced Search Functionality: Implement search and filtering capabilities to quickly find targets by name, constellation, object type, or visibility
• Dynamic Catalog Updates: Support for online catalog updates and user-contributed target additions

Performance Optimizations

• Calculation Optimization: Improve astronomical calculation algorithms for faster real-time tracking and reduced battery consumption
• Enhanced Algorithms: Implement more precise orbital mechanics, atmospheric refraction corrections, and precession calculations
• Caching System: Implement intelligent caching of frequently accessed astronomical data
• Background Processing: Optimize sensor data processing to minimize CPU usage

Advanced Telescope Integration

• Device-Telescope Orientation: Track and compensate for the relative orientation between mobile device and telescope mount
• Mount Type Support: Add support for different telescope mount types (Alt-Az, Equatorial) with appropriate coordinate transformations
• Offset Calibration: Allow users to calibrate device position relative to telescope optical axis
• Multi-Device Sync: Support for using multiple devices simultaneously for complex alignments

Astrophotography Support

• Camera Integration: Add support for connecting DSLR/mirrorless cameras for astrophotography guidance
• Eyepiece/Camera Toggle: Allow users to switch between visual observation (eyepiece) and photographic modes
• Camera Settings Recommendations: Provide suggested camera settings (ISO, shutter speed, aperture) based on target type, conditions, and equipment
• Live View Integration: Support for camera live view overlay with tracking guides

Filter Management System

• Comprehensive Filter Database: Include all major filter types (broadband, narrowband, light pollution, planetary, etc.)
• Filter Outcome Prediction: Show expected results and image quality improvements for different filter-target combinations
• Equipment Profile: Allow users to save their telescope, camera, and filter combinations for quick setup
• Filter Recommendations: Suggest optimal filters based on target type and observing conditions

Additional Features

• Weather Integration: Real-time weather data and astronomical seeing conditions
• Observation Logging: Track and log observations with notes, images, and conditions
• Social Features: Share observations and connect with other astronomy enthusiasts
• Offline Mode: Full functionality without internet connection for remote locations
• AR Overlays: Augmented reality features for naked-eye stargazing assistance