Solar Hills


The artist Liliane Lijn and the astrophysicist  John Vallerga began their collaboration in 2005 on a project called “Solar Hills“. Below is a description of Solar Hills and a brief history of the collaboration. More of Liliane Lijn’s work can be found at her website:

Actual test of two Solar Hill’s spectroheliostats located in the Marin Headlands and viewed from Crissy Field

In 2005, Liliane Lijn was awarded an Arts Council International Fellowship to become artist in residence at Space Sciences Laboratory, University of California, Berkeley, in partnership with the Leonardo Network and NASA.  Lijn’s interest in science, in particular in light and its relation with matter, dates back to the early 1960’s. Shortly after her arrival, she received an email from John Vallerga, an astrophysicist working at the Lab, whose observations of solar reflections off glass windows in the East Bay Hills had led him to think of an ‘art project’. Vallerga and his fellow astrophysicist, Patrick Jelinsky, often imagined arrays of optics to duplicate (and control) the light they saw reflected off distant picture windows visible from around the bay, from their perch at the Space Sciences Laboratory far above the Berkeley campus. On receiving this email, Lijn immediately realised that Vallerga’s ideas converged with her previous work.

Vallerga’s relationship to light is normally at the photon level, as he is an expert in detecting the dim ultraviolet and visible light from distant stars and galaxies. His specialty are imaging detectors that are so sensitive, they can individually count and locate single photons. These space-based detectors are used in telescopes like the Hubble  Space Telescope in Earth’s orbit or travelling on missions to planets like Jupiter and Pluto.

Lijn has worked with light and, particularly, reflected light for many years. Her first encounter with prisms was in 1964, when she was surprised and stunned by a flash of brilliant colour that filled her pupil as she crossed a busy boulevard in Paris, France. Having reached the other side of the boulevard, she saw that a display of prisms in a shop window had sent her a message of light. Since that revelatory experience, she has used prisms to refract light and has created large installations with projected rainbows. In the 1970’s, she began to attach prisms to stones and rocks found during walks in the mountains and on beaches. At the time, she wrote: The relationship between the natural and the man made interests me… I call the stone body and the prism mind. Lijn’s placing of an array of prisms, following the curvature of a round stone in 1976, was nothing less than a model for what would become, 25 years later, Solar Hills. Lijn wanted to use prisms with the sun, however, controlling the direction of light and following the sun was a problem that she was unable to solve on her own. Meeting John Vallerga resulted in an extraordinary coincidence of vision, scientific knowledge, experience and ideas.

Liliane Lijn   Firespine, 1976

On discussion of how to deploy their reflective instruments, Lijn first saw them as secondary Suns and asked Vallerga whether they couldn’t create very large reflections so that a blue sun would be seen shining opposite our normal one. This wild idea turned out to be impractical for numerous reasons. Lijn recalled how she loved the Northern California hills and suggested they try to outline the horizon with points of refracted light.

Artist’s impression of Solar Hills 2005

A toothed hilltop in Peru: the oldest solar observatory in the Americas

From 2005, Lijn has been working on raising funds and interest in the Solar Hills Project. In 2006, she applied and received funding awards from Arts Council England and the Calouste Gulbenkian Foundation to develop Solar Hills.  With this initial seed funding, John Vallerga has, together with Pat Jelinsky and Jason B. McPhate designed a first Spectroheliostat (as they decided to call the instruments), using plastic prisms for lightness and economy. These were tested in October 2006 and proved too fragile, producing less intense colours than glass. In May 2007, they tested the first glass prism Spectroheliostat and Pat Jelinsky’s improved software. Lijn video-taped the tests, interviewing the amazed passer-byes. In the UK, Lijn researched possible installation sites in the Malvern Hills with the assistance of Art Point. In 2008, further tests were undertaken from Hawk Peak to Crissey Fields in San Francisco (

There has been much interest in the project in California and in Europe.  It was worked on by two teams of students and their professors at the Ecole Centrale in Marseille, assisted by an engineer contracted to develop it as a stand-alone installation on the Montagne Saint Victoire in Provence for 2013, in homage to the great painter Paul Cezanne. Unpredictable political problems have unfortunately cancelled the installation for Marseille and Provence, although the enthusiasm and dedication of all the many people working on it for over a year has not lessened.

Artists impressions of Solar Hills installation on Montagne Sainte Victoire


St. Paul’s in London imagined by the artist as a Solar City promenade.

Solar Cities and Solar Bridge have both been developed from Solar Hills. The Solar City project, also called Endios, the ancient Greek word for ‘light on light, brilliance, clarity’, here attempts to describe the indescribable light of pure solar reflection seen during the day as part of the urban landscape.

A current proposal is to install a minimum of 5 spectroheliostats on the rooftops of 5 different buildings along the North side of the Thames. At different times of the day, brilliant intensely coloured stars would be seen shining from the tops of these buildings by people gathering at previously chosen locations on the South side of the Thames. Solar City would take the form of a walk along the South side of the river Thames, from West to East, with stops at the London Eye, Festival Hall, Hayward Gallery, Tate Modern and the Design Museum. Solar City is a mystery walk because it is preferable for people to be surprised by what they see. No amount of pre-publicity will prepare them for this experience. When they arrive at the first location, the ‘dance of light’ sparkling on the tops of buildings will catch them unawares. No artificial light can produce this effect during the day, since it would have to compete with the sun. Solar Beacon is currently being prepared as an installation to celebrate to 75th anniversary of the Golden Gate Bridge. It is planned that the installation will take place on the 27th of May and last throughout the summer of 2012.


Liliane Lijn   2012

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