About this page
The sky of İstanbul, kept in real time. The page shows today’s civil dawn, sunrise, sunset, civil dusk and day length—for İstanbul by default, or for one of ten cities—and its background follows the sun’s altitude, so it always wears the color of the hour. The times are worked out from the city’s coordinates, in the city’s own time zone.
Questions
What is civil twilight?
The stretch when the sun sits less than six degrees below the horizon—civil dawn before sunrise, civil dusk after sunset. There is usually enough light to read outside, and it is the boundary many countries use for headlights and flight rules.
How accurate are the times?
They are computed with a standard almanac algorithm and usually land within a minute or two of published tables. Horizon, altitude and unusual atmospheric refraction can shift the real moment slightly.
Can I see a city other than İstanbul?
Pick one from the row beneath the times, or add ?city= to the address, e.g. /twilight/?city=london. The times come from each city’s fixed coordinates, shown in that city’s own time zone.
Why does the page change color?
The background follows the sun’s altitude for the chosen city—deep night blue through dawn amber into daylight—recomputed every half minute, so the page always wears the color of the hour.
More instruments: the phase of the moon, the turn of the seasons and days between dates—or see all of them. From the writing: The Cove.