After you install and configure Sundial, it will automatically display an image from the scene you selected every time you start your computer, and update it periodically over the course of the day. The exact image displayed at any moment depends on the current time of day, the date, and your geographic location. Sundial calculates the time of sunrise, sunset, dawn and dusk at your location and arranges for these events to occur at the same time on your computer. Sundial can also display still pictures on your desktop that do not change.
Larger sizes are also available for a nominal charge.
The movies display a new image every 5 minutes for an entire 24 hours and the transition between the images is smooth and virtually instantaneous. About the photographer Geographical Database Sundial needs to know your location to accurately calculate the time of sunrise and sunset. If you do not know your latitude or longitude, you can look up this information on the US Geological Survey web site.