At 78 degrees north latitude, when the sun sets at the end of October and does not rise again for almost four months, the sky above Adventdalen becomes an unparalleled theater. The valley that opens behind Longyearbyen — the only real town in the Svalbard archipelago — hosts conditions of darkness that few inhabited places in the world can boast: zero artificial light pollution beyond the edges of the small urban center, crystal-clear Arctic air, and a clear horizon that allows for following the northern lights from the horizon to the zenith.
Longyearbyen is accessible by direct flights from Oslo and Tromsø operated mainly by Norwegian and SAS, and with about 2,400 inhabitants, it is the northernmost inhabited place on the planet with an international airport. From here, Adventdalen is traveled east along Route 17, the only paved road on the island of Spitsbergen, which winds for about 45 kilometers before dissolving into the glacial tundra. It is along this corridor that the scientific facilities and observation points that make this valley unique are located.
The Kjell Henriksen Observatory: the window to the aurora
The Kjell Henriksen Observatory, inaugurated in 2008 and managed by the University of the Arctic (UNIS) in collaboration with the Norwegian Space Research Institute, is the most important scientific facility in the valley for the study of the northern lights. Located at about 520 meters above sea level on the Breinosa plateau, it houses over 30 optical instruments from various international institutions, all oriented towards the polar night sky. Its white domes, visible from the main road of the valley, have become a visual symbol of Arctic research.
The observatory is not continuously open to the public, but UNIS periodically organizes open days and guided tours during the polar night season, generally between November and February. Contacting the university directly before the trip is essential to check availability and access methods. Even just approaching the facility at night, with the illuminated domes and the auroras above them, is a visually powerful experience.
EISCAT and Ionospheric Research
Further down the valley, the parabolic antennas of the EISCAT (European Incoherent Scatter Scientific Association) facility dot the landscape with their industrial geometry. EISCAT operates scientific radars to study the ionosphere and the Earth's magnetosphere, and the Svalbard station — active since 1996 — is one of the few in the world positioned directly under the auroral oval, the circumpolar band where auroras are more frequent and intense. The antennas are visible from the road and represent an extraordinary photographic detail when the green sky of the auroras looms above them.
The presence of these scientific infrastructures is not coincidental: Adventdalen is located in a geographical position that almost perfectly coincides with the heart of the magnetic auroral oval. This means that auroras here are not an occasional phenomenon during peaks of solar activity, but occur regularly almost every clear night during the polar dark months, regardless of the solar cycle.
The Polar Night: When to Go and What to Expect
The polar night in Longyearbyen lasts from October 26 to February 15, with about 110 days of total darkness. During this period, the sun never reaches the horizon, and even in the central hours of the day, the sky remains dark or at most is traversed by a faint bluish luminescence. For observing the auroras, the months of November, December, and January offer the best conditions: absolute darkness for all 24 hours, an average temperature between -10°C and -20°C, and a very high auroral frequency.
A fundamental practical tip: auroras do not follow fixed schedules, but activity is statistically more intense in the central hours of the night, between 10:00 PM and 2:00 AM local time. The Space Weather Live app and the Norwegian Meteorological Institute's website provide reliable forecasts on the KP index, which measures geomagnetic intensity. A KP of 3 or higher is sufficient in Svalbard for auroras visible to the naked eye. Bringing appropriate thermal layers — with temperatures that can drop below -25°C with the wind — is not optional but an absolute necessity.
How to move in the valley and safety
Venturing into the valley beyond the limits of Longyearbyen requires being aware of a specific local rule: outside the urban perimeter, the regulations of the Governor of Svalbard recommend traveling armed or accompanied by a licensed guide, due to the presence of polar bears. Local guides offer night excursions by snowmobile or on foot with complete equipment and rifle, with prices generally ranging from 1,200 to 2,500 Norwegian kroner per person depending on the duration. Many agencies in Longyearbyen offer specific packages for aurora observation that include stops at the darkest points in the valley, away from the city lights.
Even staying near the inhabited center, the eastern side of Longyearbyen — where the valley opens to the east — offers sufficiently dark skies to observe intense auroras without the need for an armed guide. Parking near the Svalbard Museum, open year-round, is a convenient and safe starting point for those who want to begin orienting themselves before venturing further.
