Blue Hour Calculator · Golden Time for Photography | Blue Moment Query Tool
Precisely calculate the blue hour before sunrise and after sunset based on solar altitude angle. Display morning/evening blue hour periods, duration, and best shooting times. Supports global location queries, pure local computation, privacy secure.
💡 Classic blue hour range: -6° ~ -4° | Extended range: -8° ~ -4° (longer duration)
Blue Hour · Details
👈 Enter coordinates and click Calculate
Supports any location worldwide. Click "Use My Location" for instant positioning
Blue Hour Calculator · Complete Guide
📌 Tool Overview
Blue Hour Calculator is a professional photography assistant tool that helps photographers precisely capture the golden shooting period before sunrise and after sunset. Based on astronomical algorithms, it calculates solar altitude angles in real-time, providing minute-accurate blue hour data.
- Supports any location worldwide - just enter coordinates
- Customizable solar altitude angle range for different photography needs
- Displays sunrise/sunset times and nautical twilight periods
- Provides professional photography tips for beginners and pros alike
- Pure frontend implementation - all calculations done locally, privacy protected
- Responsive design - works smoothly on mobile, tablet, and desktop
📝 How to Use
- Enter latitude and longitude coordinates of your location (or click "Use My Location")
- Select the date you want to query
- Adjust the blue hour angle range as needed (classic range: -6° ~ -4°)
- Click "Calculate Blue Hour" to view detailed results
- Check morning/evening blue hour times, duration, and photography tips
📐 Calculation Principle
This tool is based on the SunCalc astronomical library, using the binary search method to precisely calculate the time when the sun reaches a specific altitude angle:
Blue Hour Definition: The period when solar altitude is between -6° and -4°
Calculation Method: Using sunrise/sunset as boundaries, binary search pinpoints the exact time when the sun reaches the specified altitude
Twilight Classification: Civil Twilight (0° ~ -6°) → Nautical Twilight (-6° ~ -12°) → Astronomical Twilight (-12° ~ -18°)
📷 Photography Tips
- Preparation: Arrive 15 minutes early to set up your tripod
- Camera Settings: Use RAW format, low ISO, small aperture, try long exposure
- Composition: Use water reflections and city lights to create warm-cool contrast with the blue sky
- Post-processing: Properly lift shadows, reduce highlights, enhance blue saturation
⚠️ Important Notes
- Weather and air quality significantly affect blue hour visibility - cloudy or hazy conditions will diminish the effect
- In high-latitude regions, summer may have no complete blue hour, while winter has longer durations
- Results are displayed based on your local time zone
- "Use My Location" requires browser geolocation permission