Way More Than Sunrise And Sunset

This morning when I woke up a little before 6:30 I sensed that it was a tiny bit lighter outside than usual. Could the days be getting longer?

The answer was yes, according to my friend Google, who told me that today First Light was 6:38 am. However, they also threw in some terms that I didn't know, like Astronomical Twilight, Nautical Twilight, and Civil Twilight. Then at the end of the day they repeated the terms in backwards order (Civil, Nautical, Astronomical).

So I went down an internet rabbit hole to find out what the heck all those terms meant. This is what I found:

• Astronomical Twilight begins - when the sun's center is 18 degrees below the horizon
• Nautical Twilight begins - when the sun's center is 12 degrees below the horizon
• Civil Twilight begins - when the sun's center is 6 degrees below the horizon
• Sunrise - when the upper edge of the sun's disk appears above the horizon
• Transit - when the sun reaches it's highest point in the sky
• Sunset - when the upper limb of the sun disappears below the horizon
• Civil Twilight ends - when the sun's center is 6 degrees below the horizon
• Nautical Twilight ends - when the sun's center is 6 degrees below the horizon
• Astronomical Twilight ends - when the sun's center is 18 degrees below the horizon

Picryl

Five years ago: Writing By Witness