Trivia: there is no such thing as dusk or dawn in meteorology. Officially, both time periods are called twilight and there are three kinds.
Civil Twilight is when the sun is zero to 6 degrees below the horizon and it is characterized by “it ain’t dark yet.” You can do things like read a book without additional lighting.
Nautical Twilight is when the sun is between 6 and 12 degrees below the horizon. You can walk around and not bump into things. You can see shapes but not much detail.
Astronomical Twilight is when the sun is between 12 and 18 degrees below the horizon. Until the sun is 18 degrees below the horizon, the dimmer stars in the sunward direction are not visible.
The duration of these twilights depends on time of year and latitude. The more the sun has to slant to get to the horizon, the longer the twilights last. In the tropics the sun plunges down to the horizon nearly vertically so it gets dark quickly.
Trivia: there is no such thing as dusk or dawn in meteorology. Officially, both time periods are called twilight and there are three kinds.
Civil Twilight is when the sun is zero to 6 degrees below the horizon and it is characterized by “it ain’t dark yet.” You can do things like read a book without additional lighting.
Nautical Twilight is when the sun is between 6 and 12 degrees below the horizon. You can walk around and not bump into things. You can see shapes but not much detail.
Astronomical Twilight is when the sun is between 12 and 18 degrees below the horizon. Until the sun is 18 degrees below the horizon, the dimmer stars in the sunward direction are not visible.
The duration of these twilights depends on time of year and latitude. The more the sun has to slant to get to the horizon, the longer the twilights last. In the tropics the sun plunges down to the horizon nearly vertically so it gets dark quickly.