Quote:
Originally Posted by hellosailor
David-
"sunset" is an almost meaningless term.
Civil Sunset, today, in NYC, is at 6:52pm.
Nautical sunset, 7:23pm
Astronomical sunset, 7:55pm, all in DST.
In any case, if the guy was driving west into the sunset, he'd be blinded by it for a good our before, as well.
Personally I prefer older definition of sunset, that being the time when a black thread and a white thread both held out at arm's length appear to be the same color. |
Actually, sunset is a very meaningful term: the point at which the sun goes below the horizon. May vary slightly from
forecast depending on height of observer and atmospheric pressure.
I believe you (or whatever source you used) misspoke when referring to astronomical, nautical, and civil
sunset. The proper terms are astronomical, nautical, and civil
twilight, and all have very specific meanings. The times given in your post are the end of (insert name) twilight.
Civil twilight is defined as the time when you don't need headlights on the road. It's the
legal definition for "it's still light out" (i.e. don't need to use headlights on the road) and is the twilight that most corresponds to your definition of "the time when a black thread and a white thread both held out at arm's length appear to be the same color."
Nautical twilight is of great interest to cruisers that delve into the art of celestial. It is the time at which it is dark enough to see the first stars, but still bright enough to see clearly see the horizon.
The end of astronomical twilight is the point at which the sun is no longer contributing to the night sky brightness. It's the point at which astronomical researchers can start taking data.
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