Sun Simulator

The Sun Simulator is a sophisticated web application that visualizes solar position throughout the day and across seasons with stunning accuracy. It combines astronomical calculations with an intuitive compass rose interface to help photographers, architects, solar installers, and outdoor enthusiasts understand exactly where the sun will be at any given time and location. The interactive map-based interface makes celestial mechanics accessible to everyone, transforming complex astronomical data into intuitive visualizations.

Astronomical Precision

The application calculates solar azimuth and elevation using precise astronomical algorithms based on Jean Meeus's implementations, accounting for your exact latitude and longitude down to the meter. It factors in atmospheric refraction, the equation of time, solar declination variations, and even the slight differences caused by Earth's elliptical orbit. Users can scrub through time to see how sunlight angles change throughout the day, compare different seasons with solstice and equinox presets, and identify optimal times for solar exposure or shade with minute-by-minute precision.

The compass rose visualization makes it immediately clear which direction the sun rises and sets from any location on Earth, with precise azimuth readings overlaid on an interactive map powered by Leaflet. The sun path arc shows the entire trajectory across the sky, with markers for sunrise, solar noon, and sunset. Color-coded zones indicate golden hour periods, blue hour transitions, and civil/nautical/astronomical twilight phases—critical information for photographers planning shoots.

Interactive Features

Built with modern web technologies including Canvas for high-performance rendering, the simulator features smooth 60fps animations, responsive touch controls optimized for mobile devices, and real-time calculations that update instantaneously as you adjust location or time parameters. The timeline scrubber allows you to play through an entire day's sun movement in seconds, or advance frame-by-frame for precise analysis. Date controls let you jump to solstices, equinoxes, or any arbitrary date to compare seasonal variations.

The location picker integrates with browser geolocation for instant positioning, or accepts manual coordinate input for planning trips to unfamiliar locations. Search functionality powered by geocoding APIs lets you enter city names, addresses, or landmarks. The map layer supports multiple basemaps—satellite imagery, topographical maps, or street views—giving context to the sun's position relative to local terrain and structures.

Professional Applications

For solar panel installers, the simulator calculates optimal panel angles for maximum energy capture throughout the year, shows shadow patterns cast by nearby buildings or trees, and estimates seasonal energy production variations. The data export feature provides detailed tables of solar angles, sunrise/sunset times, and day length for entire years, enabling precise system sizing and performance predictions.

House hunters find the tool invaluable for evaluating natural lighting in potential homes. Before scheduling a showing, you can visualize exactly how sunlight will move through the property at different times of day and throughout the seasons. Check if that north-facing living room will get any direct sun, whether the backyard will be shaded by the neighbor's house in winter, or if the bedroom will catch harsh morning light. These insights help identify deal-breakers before wasting time on visits.

Architects and building designers use the tool to analyze natural lighting opportunities, plan window placements for passive solar heating, design overhangs for summer shading while allowing winter sun penetration, and ensure compliance with daylight access regulations. The visualization clearly shows how sunlight will enter spaces at different times of day and year, enabling evidence-based design decisions that optimize for energy efficiency and occupant comfort.

Photographers leverage the simulator for planning landscape shots during golden hour, determining when sunlight will illuminate specific features from desired angles, scheduling portrait sessions with optimal natural lighting, and scouting locations remotely before committing to travel. The ability to preview exactly where and when the sun will be eliminates guesswork and ensures you're in the right place at the right time.

Educational Value

Beyond professional applications, the Sun Simulator serves as an educational tool that makes celestial mechanics intuitive and accessible. Students can observe how Earth's axial tilt causes seasonal variations in sun path, understand why summer days are longer than winter days at different latitudes, and visualize the midnight sun phenomenon in polar regions or equatorial sun patterns near the equator.

The tool demonstrates why solar panels should be tilted differently in different locations, how sundials work and why they need latitude-specific designs, and why buildings in the northern hemisphere have south-facing windows for maximum solar gain while southern hemisphere buildings favor north-facing orientations. These concepts, often abstract in textbooks, become immediately clear through interactive visualization.

Technical Implementation

The implementation uses SunCalc.js for astronomical calculations, providing sub-degree accuracy across all latitudes and dates. Canvas rendering ensures smooth performance even on older devices, with careful optimization of draw calls and efficient memory management. The responsive design adapts seamlessly from desktop browsers to mobile phones, maintaining full functionality across all screen sizes.

Real-time performance is achieved through incremental calculations—only recomputing changed values rather than recalculating everything on each frame. State management keeps the UI snappy even during rapid timeline scrubbing, and Web Workers handle complex calculations off the main thread to prevent UI blocking. The result is a fluid, responsive experience that feels instant despite the mathematical complexity happening behind the scenes.