An observation

From time immemorial, the stars and the Moon have always accompanied the nights of mankind. Both guide and source of inspiration, the night sky occupies a central place in the life of Homo sapiens. Unfortunately, since the beginning of the industrial era, the stars have disappeared. When night comes, how many of us have the chance to observe a black sky, in deep darkness?

Today, the starry sky is subject to all kinds of pollution: atmospheric (anthropogenic gases), luminous (night lighting of cities and homes) and, from now on, the proliferation of space debris and communication satellites visible from Earth.

Thus this fabulous spectacle that is the starry sky, this scientific and cultural heritage of inestimable value, is threatened with erasure.

What are the solutions ?

In recent years, initiatives have multiplied in favor of the protection of the starry sky, perceived as an endangered environment like primary forests or coral reefs.

The label of « International Dark Sky Reserve » is one of the most effective. Granted by the International Dark-Sky Association (IDA), it is awarded to territories with a sky of exceptional quality, where actions are implemented for its protection and its development. It is around this concept of « Dark Sky Reserve » that our project is based.

Our project

Our project takes place in California, a state where both the space industries most damaging to dark sky quality and the communities most committed to its preservation are concentrated.

The « Starry Walk » combines a walking adventure and a campervan ride, two parallel journeys to illustrate two states of the California sky: the « pure sky of the origins » of which pockets remain in the interior desert and the « dazzling sky of the metropolis » which dominates the urbanized regions of the coast.

This hybrid project consists, on the one hand, of exploring dark sky reserves on foot, partly at night; on the other hand, of driving along the Pacific coast in an van. Throughout, interviews will be conducted with astronomers, space entrepreneurs, dark sky preservation activists and other stakeholders.

These exchanges will be reflected in a walking story published in the collection Mondes Sauvages at Actes Sud publisher in France and an audiovisual documentary. Finally, an important pedagogical component will be deployed in the two years following the realization of the project, in order to popularize the themes related to the sky to the general public, especially to the younger generations.

Our objective

Both a pedestrian adventure and a car journey, a documentary investigation and an artistic experience, the « Starry walk » thus pursues an objective of scientific popularization, at the heart of the project.

Our approach is part of a global movement to reconnect humankind with nature – including that neglected and unrecognized component of the natural world that is the sky above our heads.


Julie and I share the same wonder for the starry sky and an equal concern for the threats that weigh today on this nocturnal splendor.

However, concerning this natural heritage, like so many others, forests or mountains, oceans or wetlands, the question arises of a useful commitment and an effective action. How can simple citizens who love ecology contribute to the preservation of the dark sky? What can they do, apart from militating in associations for the reduction of night lighting (done!), installing bat nesting boxes in their garden (done!) or equipping their home with dimmer bulbs (in progress)?

We thought about it. It seemed to us that we could effectively serve the cause by developing a project that would enhance our respective backgrounds. Julie is a journalist with a passion for photography; Olivier is a writer and multimedia scriptwriter, as well as a long-distance walker and member of the French Explorers Society.

The IDA label is awarded to territories with a sky of exceptional quality, where actions are implemented for its protection and its development.

A few weeks before the beginning of the global health crisis, we wrote a project, The starry walk, combining two parallel journeys (on foot and in an van), a book and an audiovisual documentary, completed by educational actions reaching out to the young public.

Olivier’s walking adventure will take place in the mountains and inland deserts of the state of California, US, through « International Dark Sky Reserves » as defined by the American association of worldwide influence IDA (International DarkSky Association).

It is a question of going to meet the pure sky of the origins, as preserved as possible from human activities and the nuisances which they generate. This is why this walk will continue partly at night.

Julie’s camper-van route will follow the Pacific coast of the same state, essentially urban. She intends to illustrate the dazzled sky of modern metropolises, with little or no stars. It is a journey with a documentary purpose.

Exploring this double reality, the sky of the cities tarnished by pollution and the natural sky teeming with stars, such is the motive of our journey, on foot and in van, through California.

Products of this double adventure, a book and a film will be addressed to the general public, still little sensitized to the protection of the dark sky. They will be accompanied by an important popularization device, proposed to European schools thanks to the participation of a professional scientific mediator, Tania Louis.

All things considered, it is a matter of making the starry sky known and loved, just as Jacques-Yves Cousteau made the ocean depths known and loved, in the 1950s, through his famous feature film The Silent World.

Twin views of Olivier’s (in blue) and Julie’s (in yellow) journeys through California.


Our project targets a hotbed of astronomy and space adventure, which is also a leading region in the development of « Dark Sky Places. »

The United States has one « Dark Sky Reserve » the Central Idaho Dark Sky Reserve in the north, and several « Dark Sky Parks » throughout the country. There are sites in Utah, Pennsylvania, New Mexico, Texas, Michigan… but one of the largest concentrations is in California, where no less than three sites have been identified, while five others are candidates for the label.

It is also in California that several « Dark Sky communities » have been formed, bringing together astronomers and simple amateurs of the starry sky for observation sessions. There are Dark Sky communities, for example, in Borrego and in Julian.

However, if California gathers some of the most active communities in the protection of the dark sky, it is also among the American states where this natural treasure is the most threatened.

The presence of two huge coastal conurbations (Los Angeles and San Francisco/Oakland/San Jose) and many medium-sized cities with populations of more than 100,000 (Lancaster, Santa Clarita, Bakersfield…) induces light pollution whose effects can be felt up to several dozen kilometers inland.

In addition to the effects of human activities based on the ground, we can add, as we said, the harmful consequences of space programs, in particular those of Internet satellites. The laboratories and companies involved in these projects and, in general, the world leaders in space exploration often have their headquarters in California. This is the case of SpaceX, based in Hawthorne in Los Angeles County, the Jet Propulsion Laboratory in Pasadena, Rocket Lab and Virgin Orbit in Long Beach, etc.

Thus, California is both the epicenter of the threats to the dark skies today and one of the territories that is most actively working to preserve them. Peril and salvation are combined there. This is why we have chosen this state, in preference to others, as the location for our journey to meet the starry sky.

Walking is an ideal way to approach sky observation sites, especially at night. Encountering the “wild sky” as it was for humans of the past, i.e. far from sources of light pollution (public lighting) or chemical pollution (exhaust fumes and industrial waste), is an unforgettable experience.

Author of several books on hiking and its contemporary variants (urban and peri-urban micro-adventures…), Olivier undertook, in 2010, a world tour by foot in stages which continues from year to year. It reached Moscow in 2019, before the health crisis and then the war in Ukraine suspended his steps and those of his teammates.
For more information: site GEOPEDIS.

Olivier’s journey will consist of walking between two California cities: the town of Julian, located in San Diego County, California, 56 miles east of San Diego and 137 miles south of Los Angeles, and the city of San Francisco. The two cities are 518 miles apart by road, or about 1,400 miles apart by trail. This distance is equivalent to the distance that Olivier covers in two stages of his round-the-world trek (see inset), that is, two months of sustained walking.

The starting point, Julian, was chosen for its large community of starry sky enthusiasts, accredited in 2021 by the International Dark Sky Association. The inhabitants of this former gold mining settlement, established at the foot of the Cuyamaca Mountains, proudly claim to belong to the « 1% of Americans who can still see the Milky Way ».

A few dozen kilometers away is another IDA-labeled community, Borrero Springs, and a Dark Sky Reserve that follows the contours of Joshua Tree National Park.

Once these Southern California stages are connected, Olivier will join the Pacific Crest Trail at Santa Rosa which runs for 2635 miles from the Mexican border to the Canadian border. He will then take this very wild trail whose California route, between deserts and mountains, visits several national parks and crosses high altitude passes — including the highest point of the route, the Forester Pass at 13153 feet.

Overview of the projected march of Olivier.

Depending on the progress of his walk, Olivier may agree to a detour in the Death Valley and the Telescope Peak which dominates it: this California mountain owes its name to the exceptional panorama which one discovers at its top (11047 feet). It is a famous site for stargazing.

Telescope Peak / Death Valley National Park variant

Olivier plans to leave the Pacific Crest Trail at the latitude of San Francisco, which he will reach by following the valley of Yosemite Park. This park includes many dark sky viewing sites, such as Glacier Point where amateur astronomers have the habit of installing their telescopes.

The « starry walk » combines sporting adventure with aesthetic, even artistic experience.

First of all, it is an excursion on foot, to the meeting of various landscapes and grounds: the high and medium mountains, the forest, the desert, the stony plain and some rare villages. Taking place at times on marked paths, at times in the wilderness, this six to eight week trek will allow Olivier to cover a significant distance, up to 1,400 miles in total.

At the end of each day of walking, a camp is set up in an area preserved from light pollution, and in the open, to clear the sky.

The observation of the starry sky can then begin. It is done with the naked eye and without instruments, but by taking still or animated pictures according to different methods (point stars, light trails, star trails, night time-lapse, etc.). Then, weather permitting, Olivier will experiment with positioning and navigation with the stars using techniques developed in the past by Portuguese sailors, Polynesian explorers and African caravaneers. The purpose of these experiments is not so much to compete with modern GPS as to re-establish a functional link with the starry sky, the sky to which travelers for millennia have entrusted their route in open terrain.

These stops will also allow Olivier to measure luminosity in different directions (towards the west and the urbanized coastline, towards the east and the interior), thanks to two devices: a classic luxmeter and a Sky Quality Meter, a small box used by amateur astronomers to measure light pollution. The data collected in this way will be compared with those recorded by Julie, at regular intervals, on her own route.

The next day, the tent is dismantled and the camp moved from 12 to 20 miles, in a different setting (new orientation, change of altitude) to reveal another aspect of the sky.

This trek has a particularity: it will take place partly at night. The schedule of the night walks will be defined according to the phases of the moon, in order to limit as much as possible the light interference of our satellite.

While Olivier will walk through the interior of California in search of the pure sky of his origins, Julie will travel the Pacific coast in a rented camper-van, under the dazzling skies of the modern metropolis. Julie and Olivier will meet, far and wide, in camps accessible to vehicles as well as to travelers on foot.


For most of her route, Julie will take California State Route 1, better known as the Pacific Coast Highway, which stretches alongside the Pacific Ocean through vast, densely populated conurbations: Los Angeles (18 million inhabitants), San Francisco – San Jose (7 million), etc.

His journey will begin like Olivier’s in the town of Julian, at the foot of the Cuyamaca Mountains. An incursion into the interior will allow Julie to approach the deserts of Anza-Borrego, Colorado, and Mojave on the edge of Joshua Tree National Park, a dark sky reserve labelled by the IDA which constitutes for the inhabitants of the California coast « the closest place to observe the stars under a relatively dark sky », according to the site of the association.

Overview of Julie’s car journey

Through the valleys of Yucca and Morongo, then San Bernadino in the suburbs of Los Angeles, Julie will then visit the belt of astronomical observatories that dominate the City of Angels. .

The observatory route followed by Julie north of Los Angeles.

She will finally turn towards the Pacific coast, north of the megalopolis, at the height of Santa Monica. From then on, Julie will follow the tortuous coastal highway, due north, to the San Francisco Bay.

The 91 cm Ø telescope of the Lick observatory, assembled in 1888.

En route, Julie will make frequent forays into the hinterland to connect with sky observation sites accessible by road, either natural (peaks, promontories, lookouts) or man-made (astronomical observatories). Among the former, for example, is the partially pedestrianized Mulholland Drive ridge road that runs through the heights of Los Angeles. Among the latter are numerous observatories, scattered between San Diego and San Francisco: Palomar Observatory, Lick Observatory on Mount Hamilton, Griffith Observatory, Stony Ridge Observatory, Mount Wilson Observatory, etc.

During her car journey, Julie’s secondary task will be to illustrate the effects of hyper-modernity (light and air pollution…) on the visual aspect of the starry sky. She will measure the ambient luminosity with the simple equipment described in the previous section. Under a sky that we guess is poor in stars, she will also carry out, from time to time, counts of stars by sectors, a method used in astronomy to establish what is called the « visual limit magnitude » of the eye or of optical instruments in given conditions.

However, her main mission will be to conduct interviews with various players and witnesses of the dark sky residing in California cities. As a professional journalist, she will try to shed light on the various, even antagonistic, points of view on the stakes of protecting the starry sky.

Listening, for example, to those who want to preserve the darkness by reducing city lighting, but also to those who wish to maintain this lighting in the name of safety in public spaces. To meet the supporters of satellite Internet, a promise of connection for a large fraction of humanity, but also to know their opponents, who accuse this technology and its thousands of nanosatellites of infesting the night sky. These are the debates that are going on today in the communities that are mobilized on these subjects.

In total, Julie will conduct a dozen in-depth interviews with individuals and professionals, linked in one way or another to the dark sky. Her research has already identified a certain number of contacts in the following categories :

1 / amateur astronomers, especially those involved in the new trend of « participatory astronomy » ;

2 / executives or communication officers of space companies ;

3 / elected officials and local politicians committed to dark sky preservation ;

4 / representatives of indigenous cultures. With 723,000 individuals claiming to be Indigenous American, California has the second largest Indigenous American population in the United States ;

5 / where appropriate, urban planners, architects, urban lighting professionals and other specialists who can provide technical expertise on the subject.

Some of these interviews will be conducted in person, recorded and filmed. For practical and organizational reasons, the remaining interviews will be conducted remotely, by videoconference or by means of questionnaires sent by e-mail.


It is in 2021 that Stéphane Durand, the director of the collection Mondes Sauvages at Actes Sud publisher, proposed for a writing of a book dedicated to the « wild sky », in the spirit of this collection, both literary and scientific, which intends to « rethink the relationship between man and nature » by « listening to living beings ».

Can the pure sky, especially the starry sky, be considered as an endangered species, like the tiger or the swordfish? If so, what perils threaten this natural treasure? Conversely, what actions can be taken to preserve the purity of the sky and allow our children and grandchildren to contemplate the thousands of stars still visible to the naked eye in certain regions of the world?

These are some of the questions that will be addressed in the book, which is both an adventure book and a journalistic investigation.

On the strength of its commercial and media success, the Mondes Sauvages collection has established partnerships with television producers. Some of the works published in the collection are thus destined to become feature-length documentaries, broadcast on the French-German Arte TV channel.

Recently presented to these producers, the project of the « starry walk » has aroused particular interest. This encouraging feedback makes us hope that a TV documentary on our double adventure can be shot in professional conditions, with a dedicated team and the required means.

If this proposal is turned down, Julie and I still intend to leave a visual and sound trace of our California journeys. If necessary, we will film with the semi-professional equipment that many adventurers use in the field today. The broadcasting of a self-produced documentary follows the traditional circuit of festivals, but also online platforms and specialized travel and adventure channels.


Public presentations will accompany the release of the book and the film. They will take the form of conferences, round tables and other evening debates. They will be scheduled at book and travel fairs, during festivals dedicated to hiking and adventure, or occasionally within associations, schools, business clubs, etc.

Of course, the social networks will echo it. The last preparations of the trip, its implementation, its aftermath and its consequences will feed dedicated accounts on the most popular platforms (Facebook, Twitter…).

The lectures will be given in French as well as in English. Artist in residence at Randell Cottage de Wellington, New Zealand, for six months in 2008, Olivier has given numerous talks in English at universities and cultural centers.

Whenever possible, meetings will be organized in the United States, with the complicity of the local Alliances françaises and Instituts français. If the book is translated into English or if the film is shown internationally, events like those planned in France will be organized for the American public.


However, in order to make a more lasting impression on people’s consciences and to reach in particular the younger generations, often reticent to traditional forms of information sharing, we have thought from the beginning of the project to develop educational devices with a narrative dimension: a way to tell the story of our adventure while bringing to the students effective knowledge on the preservation of the dark sky and the disciplines that it mobilizes (optics, light, electricity for lighting…)

A few months ago, we had the opportunity to exchange ideas on those subjects with a professional scientific educator, Tania Louis. Specialized in the design of educational content, Tania Louis has extensive experience working in a school context.

Doctor in biology, Tania Louis is now dedicated to scientific mediation and the design of educational content, both classic (conferences, workshops, training courses…) and more original (videos, games, theater…). Her website : https://tanialouis.fr/

Taking into account the flexibility of the project, Tania imagined a program in three complementary levels, which will allow to adapt to both the resources gleaned along our journey and the budget actually available. Tania will be in charge of the design and implementation of the final devices.


> Walking route (Olivier): about ten weeks, from August 23rd-October 26th of 2023
> Automobile route (Julie): about for weeks, from August 22nd-September 18th of 2023

Writing of the book: from October 7th, 2023 to January 1st, 2024

Elaboration of the pedagogical materials: ditto

Release of the book: spring or fall, 2024

Tour of meetings, conferences, various presentations: up to six months after the date of the book’s release, i.e. mid-2025.

Implementation of the educational materials: from 02.2024, without a defined term.


Olivier Bleys, writer – walker

Member of the French Explorers Society

An experienced writer, Olivier Bleys has published 36 books so far: novels, essays, comics and travel stories, mainly with the Gallimard publishing house (established publisher of French literature Nobel prize winners) and Albin Michel. His works have been translated into 11 languages, including English, and have won him several awards, such as two from the Académie Française.

Olivier also has extensive experience with new technologies. Independent multimedia designer, he took part in concept design of many digital products, some of which had a scientific mediation objective : for example, the three CD-ROMs developed with the team of the show « C’est pas sorcier », a famous science show broadcasted on French TV.

A walking enthusiast, Olivier Bleys set out in France on a round-the-world walk, in stages, which continues from year to year. It reached Moscow in 2019. Several of his books are related to walking and adventure.

These activities have earned him membership in the Society of French Explorers in 2016. Olivier Bleys holds the rank of Officer in the Order of Arts and Letters, one of the most prestigious awards in the French cultural field.

Julie Philippe, journalist and adventurer

A professional journalist and photographer for the last ten years, working for the major daily newspaper of the Occitanie region in France, La Dépêche du Midi, Julie does not hesitate to try out unusual activities as part of her job.

Thus, she had the privilege of spending 24 hours underground, climbing summits of more than 10,000 feet, and learning how to survive in a snowy environments!

She has worked on many scientific subjects. For example, she wrote several papers about the “blob” (Physarum Polycephalum), some articles on the rich programming of the Cité de l’Espace museum, etc. Toulouse, the French “capital of space”, where she lives, lends itself well to this type of dossier.

Passionate about travel, Julie goes where her curiosity leads her, using her favorite means of transportation: walking — the best way to capture everyday moments! Since she met Olivier, she has accompanied him on some of his adventures.

She has shared several weeks of a round-the-world walk in Russia and covered nearly 70 kilometers in one go along the Garonne canal.


For any contact, partnership proposal or information request:

Olivier Bleys, project leader

Write him a message


Julie Philippe, co-project leader

Write her a message


Read online the complete file of “The Starry Walk” (34 pages) :

Couv The Starry Walk file