CLOSER TO INFINITY #1 - Following in Jules Janssen's Footsteps: Vaonis Brings Astronomy Back to Mont Blanc
30 May. 2026
What remains of the dreams of astronomy's great pioneers?
For Cyril Dupuy, founder of Vaonis, the answer lies on the slopes of Mont Blanc.
More than 130 years after French astronomer Jules Janssen built one of the most ambitious observatories of his time on the highest summit in Western Europe, Vaonis returned to the mountain with a similar vision: to observe the sky where Earth's atmosphere gives way to the stars.
This expedition marks the beginning of Closer to Infinity, a new series of adventures created by Vaonis to explore iconic astronomical locations, celebrate the pioneers who shaped our understanding of the Universe, and prove that smart telescopes like Vespera Pro are ready for the world's most demanding expeditions.
Jules Janssen: The Man Who Wanted to Bring the Sun Closer
Although Jules Janssen is best remembered for his observatory on Mont Blanc, he was first and foremost one of the pioneers of modern astrophysics.
Born in 1824, Janssen devoted his career to studying the Sun. During a solar eclipse observed in India in 1868, he developed a groundbreaking method for observing solar prominences without waiting for a total eclipse.
This major breakthrough, alongside the work of British astronomer Norman Lockyer, contributed to the identification of helium in the Sun's spectrum before the element was discovered on Earth.
Driven by his passion for solar observation, Janssen conceived what seemed like an impossible project at the time: building an astronomical observatory on the summit of Mont Blanc.
His vision became reality in 1893. Perched at nearly 4,800 metres above sea level, the observatory provided exceptional conditions for studying the Sun thanks to a thinner and more transparent atmosphere.
More than a century later, Janssen's intuition remains as relevant as ever.
When Passion Becomes an Expedition
Credit: Eric Courcier
At Vaonis, Janssen's story resonates deeply.
Since founding the company, Cyril Dupuy has pursued a single ambition: making astronomy simpler and more accessible through instruments capable of revealing the beauty of the Universe without the complexity traditionally associated with telescopes.
When he discovered Jules Janssen's remarkable story, one idea became impossible to ignore. If Janssen had relied on the most advanced technology of his era to explore the sky, why not do the same today with a smart telescope?
That question gave birth to the first Closer to Infinity expedition.
The goal was never to set an altitude record. It was to revive the spirit of the great astronomical expeditions.
When the Mountain Has the Final Say
After months of preparation, the expedition set off toward the Mont Blanc massif carrying Vespera Pro, along with Vaonis' new weatherproof carbon-fiber tripod and everything needed to remain self-sufficient for several days at high altitude.
Just as in Janssen's time, every piece of equipment was carried by hand.
The ascent progressed smoothly until the final section.
Then the mountain reminded everyone who was in charge.
A snow bridge, weakened by recent conditions, made the final climb too dangerous.
The decision was made to turn back at around 4,600 metres above sea level, just 200 metres below the summit. The team spent the night at the Vallot shelter (4,351 m).
It was a difficult choice, but the only responsible one. In the mountains, no summit is ever worth risking a life.
A few hundred metres lower, however, the expedition found exactly what it had come for: exceptionally stable skies.
Credit: Eric Courcier
Capturing Malin 1, a Giant of the Universe
For this expedition, Cyril Dupuy wanted to image an object worthy of the challenge.
His choice fell on Malin 1, located approximately 1.2 billion light-years from Earth.
Little known outside the astronomical community, Malin 1 is considered one of the largest known spiral galaxies. Its enormous but extremely diffuse disk makes it particularly challenging to photograph.
Throughout the night, Vespera Pro collected light from the depths of the Universe.
A total of 1,646 individual images were stacked to gradually reveal the galaxy's faint structure.
Beyond the technical achievement, the image tells an extraordinary story: photons that began their journey more than a billion years ago finally reaching a telescope on the slopes of Mont Blanc.
Malin 1 Galaxy captured with Vespera Pro from the Mont Blanc massif.
Observing the Sun in Jules Janssen's Footsteps
At sunrise, it was time for the expedition's second objective.
Equipped with its solar filter, Vespera Pro turned toward our closest star.
The observing conditions were remarkable. At this altitude, atmospheric turbulence was significantly reduced, producing a particularly stable view and illustrating exactly why Jules Janssen chose Mont Blanc for his observatory more than a century ago.
The resulting image reveals several groups of sunspots, along with bright faculae associated with the Sun's intense magnetic activity.
More than 130 years after Janssen's pioneering observations, the heights of the Mont Blanc massif continue to offer a privileged view of our star.
The Sun captured with Vespera Pro
Closer to Infinity: Exploring Beyond Limits
This expedition is the first chapter of Closer to Infinity, a series through which Vaonis aims to explore iconic astronomical locations while celebrating the people whose curiosity expanded our understanding of the Universe.
It also highlights how dramatically astronomical instruments have evolved.
Where Jules Janssen once needed to build a permanent observatory atop Mont Blanc, today's smart telescope fits inside a backpack, yet is capable of capturing both the intricate details of our Sun and the faint light of a galaxy more than a billion light-years away.
Exposed to freezing temperatures, strong winds, high altitude and the demanding conditions of alpine exploration, Vespera Pro demonstrated its robustness in extreme conditions while continuing to produce remarkable astronomical images.
For Cyril Dupuy, this ascent was more than a tribute to Jules Janssen. It was a reminder that, regardless of the technology we use, astronomy remains a profoundly human adventure—driven by curiosity, exploration and an enduring desire to look up and better understand our place in the Universe.
Credit: Eric Courcier
