The geometry
How Lumavyr works.
Lumavyr turns date, time and place into an offline model of the Sun’s position. The website demonstrates that model as one continuous sky: scroll moves virtual time forward, while the native app applies the same physical ideas to real planning.
1. Calculate the solar position
Date, time, latitude and longitude determine the Sun’s azimuth and elevation. Azimuth describes the compass direction; elevation describes the angle above or below the horizon. Those values also define sunrise, sunset, twilight, blue hour and golden-hour windows. The website uses a lightweight visual approximation, while the native product is designed as an offline planning instrument.
2. Compare the Sun with the real horizon
A mathematical sunrise does not account for an obstruction in front of you. Horizon Scan captures a simplified angular profile and intersects it with the solar path. When the Sun remains below that profile, the route is marked blocked. When it clears the profile, the route becomes visible direct light. This is why two nearby locations can receive their first direct light at different times.
3. Relate direction to the composition
For photography, Lumavyr compares the subject direction with the Sun direction to find front, 45-degree, side, rim and backlight opportunities. For an alignment, the planner searches future dates for the Sun to reach a target azimuth and elevation. Saved places and compositions turn that search into a repeatable workflow instead of a one-time calculation.
4. Keep the core workflow offline
Astronomy does not require an AI model, a weather API or a user account. The calculations are deterministic and can run locally. Weather still affects whether the sky is clear, and real terrain measurements have limits, so Lumavyr provides planning information rather than a guarantee of lighting or shooting conditions.