What is the difference between sunrise and twilight

It should be obvious "Elementary, Dr. Watson" that "twilight" also occurs in the morning, before sunrise. Should I presume that the scientific terms involving Civil, Nautical and Astronomical twilight use the same solar angular standards as for evening twilight?

Or - - is there another word, other than "twilight" - - to describe the pre-dawn event? Yes, twilight occurs before sunrise and after sunset, with the same stages civil, nautical, astronomical as described above, only in the reverse order. In the morning, astronomical twilight occurs first, then nautical, then civil, before sunrise. The article did little to describe the difference.

Twilight is the period of time between when the Sun first hits the horizon and when it finally sinks below the horizon, whereas dusk begins after the Sun is below the horizon. Twilight occurs directly before dusk. If you are following the same definition for both—i. However, if you are following mixed definitions—such as nautical twilight and civil dusk—then there is technically some overlap and it could be said that nautical twilight and civil dusk occur simultaneously for a period of time.

Just in case anyone else was curious as to pronunciation - I plugged into Dictionary. Skip to main content. You are here This Week's Amazing Sky.

What Exactly is Twilight? The Three Different Types. Twilight Times on Almanac. By Bob Berman. January 8, About This Blog. Rivers and Lakes. Climate and Past Weather. Civil Twilight: Begins in the morning, or ends in the evening, when the geometric center of the sun is 6 degrees below the horizon.

Therefore morning civil twilight begins when the geometric center of the sun is 6 degrees below the horizon, and ends at sunrise. Evening civil twilight begins at sunset, and ends when the geometric center of the sun is 6 degrees below the horizon. Under these conditions absent fog or other restrictions, the brightest stars and planets can be seen, the horizon and terrestrial objects can be discerned, and in many cases, artificial lighting is not needed.

Nautical Twilight: Begins in the morning, or ends in the evening, when the geometric center of the sun is 12 degrees below the horizon. In general, the term nautical twilight refers to sailors being able to take reliable readings via well known stars because the horizon is still visible, even under moonless conditions.

Absent fog or other restrictions, outlines of terrestrial objects may still be discernible, but detailed outdoor activities are likely curtailed without artificial illumination.

Astronomical Twilight: Begins in the morning, or ends in the evening, when the geometric center of the sun is 18 degrees below the horizon. In astronomical twilight, sky illumination is so faint that most casual observers would regard the sky as fully dark, especially under urban or suburban light pollution.

Under astronomical twilight, the horizon is not discernible and moderately faint stars or planets can be observed with the naked eye under a non light polluted sky.

Before astronomical dawn and after astronomical dusk, it is astronomical nighttime, when no indirect sunlight is visible and even faint celestial objects can be seen, weather permitting. The length of twilight depends on the latitude. Equatorial and tropical regions tend to have shorter twilight than locations on higher latitudes. During summer months at higher latitudes , there may be no distinction between astronomical twilight after sunset and astronomical twilight before sunrise.

This happens when the Sun never goes more than 18 degrees below the horizon during the night. Around the North Pole and the South Pole, each day-night cycle spans an entire year. In the summer, the poles experience Polar Day or Midnight Sun , when the Sun is up in the sky for several months; in the winter, during the Polar Night , the Sun does not rise for several months.

The transitions between Polar Day and Polar Night are marked by lengthy twilight periods. Once the Sun has disappeared behind the horizon in the fall, it slowly sinks lower each day, resulting in about two weeks of civil twilight, followed by nautical and astronomical twilight periods of roughly the same length.

The opposite occurs in the spring, as the Polar Night draws to a close and the Sun begins to illuminate the atmosphere several weeks before it actually rises. Sunrise, sunset, and twilight at the South Pole. Topics: Astronomy , Sun , Atmospheric Phenomena. Sign in.