The golden hour, twilight, and the position of the sun
Posted on April 23, 2013
Most of us find it useful to know when sunrise and sunset will occur on any given day. However, knowing the timing of other solar events can also help with deciding when to undertake many activities. For example, photographers often talk of the “golden hour” when lighting conditions are better for taking photos. Keen astronomers look for the end of “astronomical twilight” so that they know they have a better chance of observing clearly the night sky. We have developed our Sun Position app to provide information on the following times of day:
- Solar noon
- Golden hour
- Civil twilight
- Nautical twilight
- Astronomical twilight
Sun Position will tell you what time these will occur on any day of the year at your current location. But what do these times mean? Below I have provided a short definition of each of these events so that you can decide which might be useful for you to know.
Solar noon is when the sun reaches the highest point in the sky. This will not necessarily happen at 12 noon measured by standard time as time zones can cover a large area. The sun will be directly overhead at solar noon at the Equator on the equinoxes.
The golden hour is often referred to as the first and last hour of sunlight in the day. As the transition from/to sunrise and sunset will vary around the world, for the Sun Position app we have defined it as starting in the evening and ending in the morning when the sun reaches 6 degrees above the horizon. On a clear day between the start of the golden hour and sunset, lighting conditions are generally excellent for photography. The sun is low in the sky producing soft light which is more flattering. Also, there is less contrast and longer shadows.
Twilight is the period directly after sunset and before sunrise. It is defined according to the position of the sun relative to the horizon and its length is dependent upon your location across the world. Twilight can be broken down into three categories: civil, nautical and astronomical.
Civil twilight is between sunrise/sunset and when the sun reaches 6 degrees below the horizon. During civil twilight the sun is below the horizon, but there is still enough scattered light to see clearly. In the morning before civil twilight starts and in the evening after civil twilight ends there is not normally enough natural light to carry out ordinary outdoor activities.
Nautical twilight is when the sun is between 6 and 12 degrees below the horizon. Before nautical twilight in the morning and after it in the evening it is generally considered too dark to navigate at sea using the horizon. General outlines of objects may be distinguishable, but there is not enough light to see detail and the horizon is indistinct.
Astronomical twilight is when the sun is between 12 and 18 degrees below the horizon. Outside of astronomical twilight, the sky is dark enough for all astronomical observations as the sun does not contribute to sky illumination.
This entry was tagged with: Sun Position