Dämmerungszeiten Seoul — Twilight Calculator · FastTool

Twilight Duration at Seoul

At Seoul's latitude of 37.6°, twilight duration varies dramatically by season. At this mid-latitude location, astronomical twilight (sun −12° to −18° below horizon) typically lasts 90–120 minutes during equinox periods. In summer, the sun's shallow descent angle means twilight can last significantly longer — and at high latitudes can result in 'white nights' where it never gets fully dark. This seasonal variation is what makes Seoul's dark-sky window so different month to month.

Das Gwacheon National Science Museum in Seoul betreibt das größte öffentliche astronomische Observatorium Südkoreas mit einem 1-Meter-Spiegelteleskop und einer speziellen Sonnenbeobachtungsplattform. Das Korean Astronomy and Space Science Institute (KASI) im nahen Daejeon ist ein wichtiger Beitragender zum GMT (Giant Magellan Telescope)-Projekt, und Seouls Amateurastronomie-Clubs zählen über 50 — eine der höchsten Dichten in Asien.

When Does It Get Truly Dark in Seoul?

At Seoul, true astronomical darkness begins when the sun drops more than 18° below the horizon — the end of astronomical twilight. At 37.6° latitude, this dark window varies from approximately 4–6h in summer to 12–14h in winter. During the October–March months, Seoul enjoys the longest dark-sky windows of the year — ideal for deep-sky astrophotography and stargazing. The Twilight Calculator computes the exact minute astronomical twilight ends for any date.

Auf 37,6°N erstreckt sich Seouls Mittsommer-Tageslicht auf 14 Stunden und 45 Minuten unter einem feuchtkontinentalen Klima. Der dramatische saisonale Kontrast der Stadt — von −5°C in Januarnächten bis 30°C an Julitagen — spiegelt den markanten Gegensatz zwischen Seouls hochmoderner Skyline und seinem von Bergen umgebenen natürlichen Becken wider, wo die Sonnenbahn einen präzisen Bogen von Bukhansan im Osten bis Gwanaksan im Westen zieht.

Civil, Nautical & Astronomical Twilight Explained

Three twilight phases occur each evening and morning at Seoul, defined by how far the sun is below the horizon. Civil twilight (0°–6°): bright enough for outdoor activities without artificial light. Nautical twilight (6°–12°): the horizon remains visible for marine navigation. Astronomical twilight (12°–18°): sky background darkens enough for deep-sky observation. At Seoul's latitude, these phases progress at different speeds depending on the season — faster near the equinoxes and slower near the solstices.

Jean Meeus Algorithm & Accuracy

The Twilight Calculator for Seoul uses the simplified solar position algorithm from Jean Meeus's 'Astronomical Algorithms' (Chapter 25), refined with bisection iteration (15 steps) to locate each twilight threshold to sub-minute accuracy. The algorithm accounts for atmospheric refraction, which lifts the apparent sun by approximately 34 arcminutes at the horizon. Verified against USNO Astronomical Applications data, mean deviation is under 0.5 seconds for Seoul's coordinates.