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Artistic transformation of an astrophysical tool : the coded mask


Patrick Chartol : multimedia artist, composer, musician, painter

Cyril Lachaud : assistant professor in high energy astrophysics at University Paris Diderot

Leif e Boman : Sound composer and Visual Artist





Contact :

Patrick Chartol :

Cyril Lachaud :

Leif e Boman :


Coded Mask Prototype


When an artistical concept comes from astrophysical science and is declined into various art mediums.
Cyril Lachaud (astrophysicist) works on coded aperture imagery and through a discussion with Patrick Chartol (artist), a collaboration project was born to explore the artistic concept coming from the coded mask patterns developed in the context of a space mission.

Background on coded aperture imaging
Astronomy arose from the observation of the sky with the visible light. Quickly, the use of mirrors and lenses allowed to focus the light to make images of the sky (telescopes …). Unfortunately the use of these techniques is not possible with x-rays and gamma rays because these energetic radiations have a far too big power of penetration. A cunning technique said «  Coded aperture imaging" allows us to solve this problem.

The figure gives the principle. A source of light is going to cross a device with holes, by which the light simply crosses, or fulls, which are going to stop the light. This device which allows the light to pass or stops is the aperture coded mask (which is usually called "coded mask"; the material which composes it is to be carefully chosen  when one want to stop x-rays and gammas, we use some lead or the tantale, for example). So, on a detection plane located below the coded mask we shall see appearing the mask shadows by measuring the received light. What makes possible the reconstruction of the origin of the light is that this shadow is unique for every position of the light source on the sky. So, with the knowledge of the pattern of the coded mask and the measurement of the light received on the detection plane we can reconstruct the image of the sky (the mathematical tool which we use is called deconvolution). Some advantages of this technique is that it works even for big field of view and when several sources are visible at the same time.

Since the 1990s, most of the space instruments which study the universe in x-rays and gamma rays, use this imaging technique.
Coded mask pattern
The image shows the starting point of the concept, self-supporting coded mask patterns developed for a space mission and declined into art.
Concept declinations
The concept of using the coded mask patterns has been declined in different art medium such as paintings, videos, printings and projects for sculpture, installation and music. We will present a preview of this work in the following pages.

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