At Gets, a new nighttime experience invites visitors to look up at the sky. From Mont Caly, perched at 1500 metres altitude, the association Kaus Australis This summer, we're offering guided planetary walks along the Sentier des Planètes. A three-hour outing, suitable for ages 12 and up, combining walking, astronomy, and a chance to disconnect.
As dusk falls, Mont Caly takes on a different atmosphere. The last ramblers head back down, the paths empty, and silence descends upon the pastures. High above Les Gets, in the Portes du Soleil region, skywatching then takes on another dimension. The colder, more stable air improves clarity, while the remoteness from light pollution allows for a sky that is rarely accessible from the valleys.
It is in this setting that Christophe Herdewyn, a member and trainer of the Kaus-Australis association, accompanies the participants. Passionate about astronomy, he won first prize in the best photograph of the year competition organised by the French Astronomical Association in 2025 with his shot «IC 443 The Medusa Nebula».
A night-time hike on the Planet Trail
The experience takes place on the Planets Trail, which was inaugurated last summer in Les Gets. Accessible free of charge all year round, this route begins at Mont Caly, where the Sun is represented by a large metal structure. The planets of the solar system are then laid out along the path on a one-billionth scale.
The walk allows you to physically gauge the distances between the celestial bodies. You leave the simple educational panel to enter a form of open-air journey, where the mountain becomes a support for observation.
Two variants exist. The short route covers 5.7 kilometres for about two hours of walking. The long route reaches 8.9 kilometres for nearly 3.5 hours. The guided outings offered by Kaus-Australis last around three hours.
Science, silence and starry sky
The appeal of this new activity lies as much in its content as in its pace. The principle is based on an accessible walk, observation breaks and simple explanations to understand the sky differently.
Children aged 12 and over can participate. Adults also find it a way to slow down, away from screens and the hustle and bustle of the village. At this altitude, night gives prominence back to the details. A constellation, a planet, a fainter glow, a story linked to the sky.
The Kaus-Australis association, whose name comes from the brightest binary star system in the constellation Sagittarius, combines training, scientific outreach, and field observation. The approach is intended to be educational without being academic, with genuine room left for wonder.
An activity accessible from this summer
The outing is on offer during Summer 2026, departing from Mont Caly. The price is set at 10 euros for adults and 5 euros for teenagers aged 12 to 17. Bookings can be made through Les Gets.
The Sentier des Planètes remains freely and fully accessible to everyone all year round, for those who wish to discover the trail during the day or return at night with a different perspective.
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