Civil Twilight (Day 318)

When planning an early swim, I often check the time of sunrise in the hopes of catching that brilliant spectacle of light when I’m out in the water. And, just as often, I’m dismayed to see day arriving long before that time. Daylight will be pouring over the streets as I drive down to the Albany Bulb and I’ll arrive at the water in full light, feeling like I somehow missed everything. Recently, I realized I should be checking to see when first light is: the twilight time preceding the sun’s actual rise when the world starts to brighten and the water begins to glow as if from some eternal source. 

I probably should have figured this out ages ago, but, alas, it was only this week I realized you can find out what time first light will be. In doing so, I learned that twilight (both at sunrise and sunset) is divided into three phases: astronomical twilight, when the sun is between 12-18 degrees below the horizon and the first tinges of light cause some stars to fade; nautical twilight, when the sun is 12-6 degrees below, producing enough light for the horizon to be visible, but it’s still dark enough that most stars are also still visible (which is why it’s called nautical twilight: ships can navigate by the stars while seeing the horizon); and civil twilight, when the sun is less than 6 degrees below the horizon and it’s bright enough to do most tasks without the aid of artificial light. Civil twilight is what precedes the actual sunrise and so when I plan my swim for sunrise, I end up arriving in civil twilight.

And so it was today. Sheila, Angie, and I met at 6:30 and the Albany Bulb was fully light, though the sun was still tucked away. As we swam along in the cold water (53/54 today), the colors shifted and the water shimmered. Birds swooped.

And, soon, the sun emerged and spilled its warmth all over the place, just in time to help us along as we went through the always painful process of getting out and getting dressed. 

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