Dämmerungszeiten Kapstadt — Twilight Calculator · FastTool

Twilight Duration at Kapstadt

At Kapstadt's latitude of -33.9°, 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 Kapstadt's dark-sky window so different month to month.

Kapstadt beherbergt das South African Astronomical Observatory (SAAO) im Stadtteil Observatory — das älteste permanente Observatorium der Südhalbkugel, seit 1820 in Betrieb. Der Tafelberg, der 1.085 Meter direkt hinter der Stadt aufragt, erzeugt ein einzigartiges orografisches Wolkenphänomen namens 'Tischtuch' — eine Wolkenschicht, die entsteht, wenn Südostwinde feuchte Luft die Bergflanke hinaufdrücken und dramatische Sonnenuntergangs-Silhouetten über dem Stadtkessel erzeugen.

When Does It Get Truly Dark in Kapstadt?

At Kapstadt, true astronomical darkness begins when the sun drops more than 18° below the horizon — the end of astronomical twilight. At -33.9° latitude, this dark window varies from approximately 4–6h in summer to 12–14h in winter. During the October–March months, Kapstadt 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 33,9°S feiert Kapstadt seine Dezember-Sonnenwende mit 14 Stunden und 25 Minuten Tageslicht — Hochsommer an der Südspitze Afrikas. Die Lage der Stadt auf einer Halbinsel zwischen zwei Ozeanen (Atlantik und Indik) bedeutet, dass die Sonne über dem Indischen Ozean aufgeht und über dem Atlantik untergeht — ein seltenes geografisches Privileg, das nur eine Handvoll Küstenstädte weltweit bieten können.

Civil, Nautical & Astronomical Twilight Explained

Three twilight phases occur each evening and morning at Kapstadt, 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 Kapstadt'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 Kapstadt 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 Kapstadt's coordinates.