Golden hour calculator for iPhone

Golden hour is an angle, not a clock

The name is the problem. Golden hour is not an hour and it does not start at a fixed time. It is a band of solar altitudes, and it lasts exactly as long as the sun takes to cross that band where you are standing. Sunlit uses the band that photographers usually mean: the sun between 4 degrees below the horizon and 6 degrees above it. Blue hour sits directly underneath, from 6 degrees below the horizon up to 4 degrees below.

Once you hold the definition in degrees, three things that look like bugs turn out to be geometry.

Why two apps print two different times

They are almost never both wrong. They are usually answering slightly different questions.

• A different band. Some tools end golden hour at the horizon, some at 6 degrees above it, some run it to 10. A two degree disagreement at the top of the band is many minutes on the ground.
• Refraction, or none. The atmosphere lifts the sun by roughly half a degree when it is near the horizon. Half a degree is about the width of the sun itself, so ignoring refraction moves sunrise by minutes.
• Your elevation, or sea level. Standing higher lets you see the sun before somebody at the shoreline does.
• The horizon it assumes. Almost every published sunrise time is the time the sun clears a flat sea horizon. Almost nobody stands on a flat sea horizon.

Sunlit takes the refracted altitude, takes the elevation of the place, and solves the crossing numerically rather than interpolating between samples, so the answer does not degrade at high latitude or on a grazing event.

How long it lasts depends on where you are

The width of the band is fixed at 10 degrees. The speed the sun crosses it is not. Near the equator the sun goes down almost vertically and the golden band is crossed in something like forty minutes. Far north the sun slides down at a shallow angle, and in high summer above roughly 70 degrees north it can sit inside the golden band from evening until morning without ever leaving it. That is why a single number copied from a photography blog is worthless, and why the app solves it for the place and the date you actually picked.

What to read on the screen

1. Open the Sky view

   The arc across the background is the altitude of the sun through the local day. The shaded band across it is golden hour, and blue hour is the strip below it. Where the arc crosses the band is where the light you want lives.

2. Read the day rail

   Underneath, in order: first light, sunrise, golden hour ends, solar noon, golden hour begins, sunset, last light. Those are solved times for the place in the header, not a table for the nearest city.

3. Drag the time scrubber

   The background is not decoration. It is interpolated from the real solar altitude at the instant you are pointing at, so four in the morning does not look like noon. Drag it to the start of the band and the azimuth underneath tells you which way to face.

4. Check it against your actual skyline

   A published golden hour assumes nothing is in the way. Sweep the camera along your horizon and Sunlit stores it as 36 sectors of ten degrees, then works out when the sun really clears the ridge or the building and how long you lose. The measured horizon is part of Sunlit Pro.

What this costs

Golden hour and blue hour for today, at the place you are standing, are free forever, along with sunrise, sunset, all three twilights, solar noon, day length and shadow length. Scouting a different date or a place you are not standing in is what Sunlit Pro opens, for one payment of 9.99 EUR. Nothing renews.

If you want the same numbers as a table rather than a picture, the Data view lists civil, nautical and astronomical twilight at 6, 12 and 18 degrees below the horizon, solar noon, day length, and how much the day grew or shrank since yesterday.