Sunday, May 5, 2013

Twilight

Twilight on Moon Lake on the Ouachita River by Burg Ransom


This morning before sunrise a cardinal sang outside my window.  I looked out and saw the pink glow in the morning sky.  This time of day is called “twilight.”  An animal active during the twilight moments is called “crepuscular.”  The diffuse light of twilight gives the forest a soft, mystical appearance, which is accentuated by fog or mist. Other terms used for this time of day are:  dawn, daybreak, dusk.

The website called www.earthsky.org is a good source of information about celestial events like phases of the moon, meteor showers, and planet visibility.   Here is their definition of twilight:  “You can define twilight simply as the time of day between daylight and darkness, whether that’s after sunset or before sunrise.  It’s a time when the light from the sky appears diffused and often pinkish.  The sun is below the horizon, but its rays are scattered by Earth’s atmosphere to create the colors of twilight.”

According to the website, there are three types of twilight defined by how far the sun is below the horizon.

Civil twilight:  It starts as soon as the sun dips below the western horizon and ends when the sun is 6 degrees below the horizon.

Nautical twilight:  It begins when it’s fairly dark outside and ends when the sun is 12 degrees below the horizon.

Astronomical twilight:  It ends when all traces of sky glow are gone or when the sun is 18 degrees below the horizon.  Now stars can be observed if the sky is not cloudy.

I bet you did not know this twilight trivia.  Nevertheless, I beseech you to enjoy all the phases of twilight for it is a magical time in the natural world.

Remember:  Nature waits for you.







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