About

Light is the fundamental variable in photography. The "Golden Hour" - the period shortly after sunrise or before sunset - provides soft, diffused light with a reddish hue, preferred for portraits and landscapes. Conversely, the "Blue Hour" offers a cold, deep blue gradient ideal for cityscapes and architecture.

This tool uses astronomical algorithms to calculate the solar elevation angle for any coordinate on Earth. It identifies the precise windows when the sun is between 6° above and -6° below the horizon, ensuring photographers never miss the critical window of optimal illumination.

Formulas

The solar hour angle ω is derived from the latitude φ and solar declination δ for a given solar elevation h.

cos(ω) = sin(h) − sin(φ)sin(δ)cos(φ)cos(δ)

Solving for time t requires converting ω to degrees and adjusting for the equation of time and longitude.

Reference Data

Phase	Sun Elevation (θ)	Lighting Characteristics
Blue Hour (AM)	-6° to -4°	Deep blue sky, cold tones, city lights visible.
Golden Hour (AM)	-4° to 6°	Warm, soft, directional, long shadows.
Daytime	> 6°	Hard, neutral, high contrast.
Golden Hour (PM)	6° to -4°	Warm, soft, increasingly red.
Blue Hour (PM)	-4° to -8°	Dark blue, decreasing contrast.

Frequently Asked Questions

Yes. The calculation engine is embedded entirely within the browser code. Once loaded, it does not require an internet connection to calculate times for the selected coordinates.

The duration depends on the angle at which the sun crosses the horizon. In summer (or closer to the poles), the sun's path is more oblique, keeping it within the "golden" altitude range for longer. Near the equator, the sun rises perpendicularly, shortening the transition.

The tool uses your device's local system time settings to format the output. If your device observes DST, the results will automatically reflect that.

The Blue Hour is the period of twilight when the sun is significantly below the horizon, and the residual indirect sunlight takes on a blue shade. It is shorter than the Golden Hour and requires faster shooting.