When does it get dark in Londen tonight?

Tonight's darkness times for Londen depend on the date and Londen's latitude (51.5°). Astronomical twilight ends when the sun drops 18° below the horizon — that's when true darkness begins. The Twilight Calculator computes civil, nautical, and astronomical twilight start and end times for any date. Enter Londen as your location above and press Calculate to see the exact times for tonight.

How long does astronomical twilight last in Londen?

Astronomical twilight duration at Londen varies by season. At 51.5° latitude (high-latitude), it typically lasts 2–4 hours during equinox periods. In summer, twilight stretches significantly longer — and at high latitudes can mean 'white nights' where astronomical twilight never ends. In winter, the steeper sun angle produces shorter twilight. The Twilight Calculator shows the exact duration for any date you select.

What is the best time for stargazing in Londen?

The best stargazing in Londen occurs when two conditions align: astronomical twilight has ended (sun > 18° below horizon) and the moon is near new moon or below the horizon. At 51.5° latitude, the longest dark-sky windows occur during the September–April months. Use the Twilight Calculator to find tonight's dark window, then cross-reference with MoonSync to check the moon phase — this gives you the 'astrophotographer's golden hours' for Londen.

Does Londen experience white nights?

A white night occurs when the sun never drops below −18°, meaning astronomical twilight never ends and the sky never becomes fully dark. At Londen's latitude of 51.5°, 51.5074° may experience white nights during June–July when the sun does not drop below −18°. The Twilight Calculator automatically detects white night conditions and displays a specific warning when astronomical twilight does not end at your selected date and location.

Twilight data for Londen

Twilight Times Londen — Twilight Calculator · FastTool

How Twilight Works at Londen's Latitude

Twilight Duration at Londen

At Londen's latitude of 51.5°, twilight duration varies dramatically by season. At this high-latitude location, astronomical twilight (sun −12° to −18° below horizon) typically lasts 2–4 hours 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 Londen's dark-sky window so different month to month.

NOAA Twilight Reference

When Does It Get Truly Dark in Londen?

At Londen, true astronomical darkness begins when the sun drops more than 18° below the horizon — the end of astronomical twilight. At 51.5° latitude, this dark window varies from approximately 0–3 (white nights possible)h in summer to 14–16h in winter. During the September–April months, Londen 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.

ESO — Twilight Reference

Civil, Nautical & Astronomical Twilight Explained

Three twilight phases occur each evening and morning at Londen, 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 Londen's latitude, these phases progress at different speeds depending on the season — faster near the equinoxes and slower near the solstices.

IAU — Twilight Definitions

Jean Meeus Algorithm & Accuracy

The Twilight Calculator for Londen 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 Londen's coordinates.

US Naval Observatory — Astronomical Applications

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Fully Dark

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Astro Dawn

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Dark Window

21:08

Civil Dusk

Frequently Asked Questions About Twilight in Londen

When does it get dark in Londen tonight?: Tonight's darkness times for Londen depend on the date and Londen's latitude (51.5°). Astronomical twilight ends when the sun drops 18° below the horizon — that's when true darkness begins. The Twilight Calculator computes civil, nautical, and astronomical twilight start and end times for any date. Enter Londen as your location above and press Calculate to see the exact times for tonight.
How long does astronomical twilight last in Londen?: Astronomical twilight duration at Londen varies by season. At 51.5° latitude (high-latitude), it typically lasts 2–4 hours during equinox periods. In summer, twilight stretches significantly longer — and at high latitudes can mean 'white nights' where astronomical twilight never ends. In winter, the steeper sun angle produces shorter twilight. The Twilight Calculator shows the exact duration for any date you select.
What is the best time for stargazing in Londen?: The best stargazing in Londen occurs when two conditions align: astronomical twilight has ended (sun > 18° below horizon) and the moon is near new moon or below the horizon. At 51.5° latitude, the longest dark-sky windows occur during the September–April months. Use the Twilight Calculator to find tonight's dark window, then cross-reference with MoonSync to check the moon phase — this gives you the 'astrophotographer's golden hours' for Londen.
Does Londen experience white nights?: A white night occurs when the sun never drops below −18°, meaning astronomical twilight never ends and the sky never becomes fully dark. At Londen's latitude of 51.5°, 51.5074° may experience white nights during June–July when the sun does not drop below −18°. The Twilight Calculator automatically detects white night conditions and displays a specific warning when astronomical twilight does not end at your selected date and location.

30-Day Observation Planner

Date	Sunrise	Sunset	Twilight End	Moon Illum.	Dark Window
Jun 29Today	03:46	20:22	—	99%	—
Jun 30	03:47	20:22	—	100%	—
Jul 1	03:47	20:22	—	99%	—
Jul 2	03:48	20:22	—	96%	—
Jul 3	03:49	20:21	—	92%	—
Jul 4	03:50	20:21	—	86%	—
Jul 5	03:50	20:21	—	77%	—
Jul 6	03:51	20:20	—	68%	—
Jul 7	03:52	20:20	—	57%	—
Jul 8	03:53	20:19	—	46%	—
Jul 9	03:54	20:18	—	35%	—
Jul 10	03:55	20:18	—	25%	—
Jul 11	03:56	20:17	—	15%	—
Jul 12	03:57	20:16	—	8%	—
Jul 13	03:58	20:16	—	3%	—
Jul 14	03:59	20:15	—	0%	—
Jul 15	04:00	20:14	—	1%	—
Jul 16	04:01	20:13	—	4%	—
Jul 17	04:02	20:12	—	9%	—
Jul 18	04:04	20:11	—	17%	—
Jul 19	04:05	20:10	—	25%	—
Jul 20	04:06	20:09	—	35%	—
Jul 21	04:07	20:07	23:43	45%	—
Jul 22	04:09	20:06	23:33	55%	57m
Jul 23	04:10	20:05	23:25	65%	1h 16m
Jul 24	04:12	20:04	23:18	74%	1h 31m
Jul 25	04:13	20:02	23:12	81%	1h 44m
Jul 26	04:14	20:01	23:06	88%	1h 56m
Jul 27	04:16	20:00	23:01	94%	2h 7m
Jul 28	04:17	19:58	22:56	97%	2h 17m