SkyChrono — Real-time Astronomical Data
SkyChrono is a comprehensive astronomical companion app that provides precise, real-time information about celestial events, sun and moon positions, twilight periods, and multiple time systems used in astronomy and navigation.
Whether you’re planning a stargazing session, timing golden hour for a shoot, or studying celestial mechanics, SkyChrono gives you the sky data you need—fast and accurately.
Key Features
🌞 Sun Tracking
- Real-time altitude and azimuth
- Sunrise, sunset, and solar noon times
- Civil, nautical, and astronomical twilight periods
- Current lighting conditions (daylight / twilight / night)
- Day length calculations
- Moon phase with illumination percentage
- Moonrise and moonset times
- Real-time position tracking (alt/az)
- Phase progression visualization
⏰ Multiple Time Systems
- Local time with timezone
- UTC
- Julian Date (JD)
- Modified Julian Date (MJD)
- Greenwich Mean Sidereal Time (GMST)
- Local Sidereal Time (LST)
📍 Flexible Location Options
- Automatic GPS-based positioning (optional)
- Manual coordinate input anywhere worldwide
- Decimal degrees and DMS (Degrees/Minutes/Seconds) formats
🔔 Smart Notifications (Optional)
- Sunrise and sunset alerts
- Moon phase notifications (new/full/quarters)
- Golden hour and blue hour reminders
- Twilight boundary alerts (civil/nautical/astronomical)
- Customizable timing
🌃 Night Vision Mode
- Red-tinted theme to preserve night vision
- Ideal for observatories and dark-sky locations
- Quick and seamless switching
📊 Data Export
- Save the dashboard as a high-resolution image
- Export data as JSON for integration with other tools
- Copy individual values with a tap
🎓 Educational Resources
- Built-in explanations for astronomy concepts
- Quick learning on coordinate systems, twilight, and time standards
- Helpful for students and beginners
♿ Accessibility
- VoiceOver support
- Accessibility labels across key UI components
Technical Details
Requirements
- iOS 18.0 or later
- Location services (optional, for automatic positioning)
- Notification permissions (optional, for alerts)
Frameworks Used
- SwiftUI
- CoreLocation
- TipKit
- UserNotifications
- Combine
Architecture
- MVVM (Model–View–ViewModel)
- Observable macro for state management
- Coordinator pattern for navigation
- Service-based design for location/time/notification logic
Key Components
- TimeService: JD/MJD/UTC/GMST/LST conversions and formatting
- LocationService: GPS + manual coordinate input
- NotificationService: Scheduling and managing alerts
- SunCalculator: Sun position and event calculations
- MoonCalculator: Moon position, phase, and event calculations
About the Developer
Hi 👋, I’m Steven Wijaya.
I build iOS apps that turn complex ideas into practical tools. SkyChrono was created to make astronomical time systems and sky-position data easy to access in real time—without ads, tracking, or subscriptions.
Connect with the Developer
Privacy Policy
SkyChrono does not track you and does not send your data to external servers. For details, see: PrivacyPolicy.md
License
Copyright © 2025 Steven Wijaya. All rights reserved.
SkyChrono — Your window to the cosmos.