April 23, 2021

The dawn/sunrise distinction — 6:01 and 6:05.

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The official sunrise time was 6:02. I love when the disc of the sun appears, but so often, like today, it's much more colorful when the sun shows itself indirectly. The line "it's always darkest just before dawn" came to mind. Clearly, it's not always darkest just before sunrise, but dawn and sunrise are not the same thing:

Dawn is the time that marks the beginning of twilight before sunrise. It is recognized by the appearance of indirect sunlight being scattered in Earth's atmosphere, when the centre of the Sun's disc has reached 18° below the observer's horizon. This morning twilight period will last until sunrise (when the Sun's upper limb breaks the horizon), when direct sunlight outshines the diffused light.

This morning, dawn began at 5:32. If you want to go out and see the sunrise, like I do, check the cloud cover percentage before you go out. If it's not 100% or 0%, you've got a shot at seeing great color in the clouds before sunrise. So notice not just the sunrise time but when twilight begins — dawn.

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