"As first glimpsed from the edge of the abyss, the Grand Canyon is a geologic marvel and a spiritual emotion. Below is a primeval void, hemmed in every where, except skyward. . . . At noon the enclosing walls seem to flatten out and are unimpressive. They lack life and form and make scant appeal to the emotions. One is aware of bigness and deepness and stillness, but not so much of form and mystery. But come back to the edge of the abyss in the late afternoon or early morning. How marvelous the transformation! The play of light and shade have pushed out immense forms from the sheer walls. They float in a purple sea of mysterious shadows. It is a symphony of mass and color. Almost a new heaven is born, and with it a new inferno swathed in soft celestial fires." - Charles E. Lummis, from the book The Grand Canyon of Colorado
I downloaded a terrific app for my iPhone, it's called Sol - "Daylight Forecaster and Solar Alarm Clock for iPhone and iPad." It's useful for those who rely on the sun and its position for recreation, work and religious observances. It was created by an amateur photographer who needed a tool to help him time the perfect shot.
The app uses GPS to determine your location and the position of the sun. It will alert you when the sun rises and sets, when all three twilight periods occur (astronomical twilight, nautical twilight, and civil twilight) and when the next solstice and equinox will take place. It's sort of a modern day sun dial and Stonehenge combined into one. The software developer calls it "the Swiss army knife of sunlight tools."
This app is really cool and a necessity for plein air landscape artists, like me, who want to keep track of the "Golden Hour." The Golden Hour or "Magic Hour" is the time of day favored by artists, photographers and cinematographers for its light. It occurs at the first and last hours of the day when the sun is at a 10 degree angle (or less) to your location. During these hours, the sunlight passes through the thickest part of the atmosphere creating a beautiful filtered light. Fields and trees are bathed in a warm, "golden glow."
The least desirable time to paint outdoors is during the middle of the day. At this time, the sun is high in the sky and intense; the shadows become short and the scenery appears flat. Most of the color in the landscape is washed out and everything has a grayish cast. Charles Lummis, quoted above, describes it best.
This app is really handy and helps me plan my painting day. With it, no matter where I am, I can arrive at the right moment to paint. In the afternoon, I set the app to alert me when the sun is at a twenty degree angle; this gives me a little extra time before the golden hour to mass in my watercolor. With this head-start, I'm at a good point in the process to capture any fleeting effect.