STORM2K

...I know this is a really stupid question but what is "civil twilight"? I never heard that phrase before!

I found the following definitions...

Civil Twilight - The period of twilight beginning (or ending) when the center of the (refracted) Sun is more than 6° below the horizon

Astronomical Twilight - The period of twilight beginning (or ending) when the center of the (refracted) Sun is more than 18° below of horizon.

Nautical Twilight - The period of twilight beginning (or ending) when the center of the (refracted) Sun is more than 12° below the horizon.

Twilight - The transition period from day to night (or night to day) when the sky is not completely dark, but the Sun has not yet set (or risen). It is technically defined as the period of time beginning (or ending) when the center of the (refracted) Sun is lower than a given elevation. Civil twilight corresponds to the Sun being 6° below the horizon, nautical twilight to 12°, and astronomical twilight to 18°.


I guess I learned something new today

Thanks for the info, Marshall. I often wondered what was meant by Civil Twilight vs. Astronomical and Nautical Twilight.

I never knew there were three phases to twilight until I went looking