Hi, All!

What's the purpose of having a difference between Actual Time, Civil Twilight, Nautical Twilight and Astronomical Twilight times, please?

The current readings for where I'm located are below.

Quote:

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Actual Time 7:28 AM CST 4:43 PM CST
Civil Twilight 6:57 AM CST 5:14 PM CST
Nautical Twilight 6:22 AM CST 5:49 PM CST
Astronomical Twilight 5:49 AM CST 6:22 PM CST
Moon 6:03 PM CST (1/1) 8:14 AM CST (1/1)

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Thanks!

The difference is the amount of diffused light in the sky.

Civil twilight is often judged as when you can tell a black thread from a white one.

Nautical twilight is when there is a visible horizon to take sightings against.

Astronomical twilight is when telescopes start or stop working, i.e. one can actually take sightings of stars.

Actual time is when the sun's disk touches or clears the horizon.

So, what's the difference between a black thread from a white one, please?

Thanks!

Quote:

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Originally Posted by Clough

So, what's the difference between a black thread from a white one, please?

Thanks!

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You forgot the purple font, I hope.

The COLOR?

Hmm, I don't think it's sarcasm... I would like to know too. It's the first time I come across that term. :o

Quote:

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Originally Posted by Unknown008

Hmm, I don't think it's sarcasm... I would like to know too. It's the first time I come across that term. :o

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Okay, telling a black thread from a white one is a very easy way to measure the amount of daylight. If there's enough light to see the difference in color, then it's day. If there isn't, it's night.

Okay...

NOW I get it! :p

Thanks!