In astronomy, the zenith is defined as the point in the sky or celestial sphere directly above the observer. It signals the highest point overhead.

It is not an abstract mathematical point, but a deeply visceral one. In fact, our physiology is so attuned to the zenith that it impacts our behavior and modulates cognitive function.

And what better proof than the galvanizing relief felt upon setting foot outdoors after a day in a windowless office? Zonk, that’s the zenith––infinite space hovering overhead.

Image1 Sky Factory Master
Open Sky Composition by Sky Factory, Zenith and Spring Blossoms.

The vastness of a wide open sky, also happens to be humanity’s most universal experience of nature. The sky heralds relief and possibility. And according to neuroscience, exposure to its atmospheric presence, allows us to experience maximum spatial polarity.

As an element in biophilic design, spatial polarity finds it roots in Appleton’s Prospect & Refuge Theory (1975), which states that surveying our surroundings (prospect) from a secure vantage point (refuge) yields spatial features that aided our survival. Over the long arc of evolution, Prospect & Refuge, or spatial polarity, acquired neurobiological roots in the pleasure response we take in places that afford wide open views of our surroundings.

When we sense our personal scale in the vastness of the troposphere, the lowest layer of Earth’s atmosphere, spatial polarity functions as a highly effective cognitive catalyst.

The swing of awareness brought about by exposure to the first six miles of vertical sky––the layer where all weather systems manifest––spurs creativity, unspools daydreaming, and yields both solace and encouragement. When we experience the zenith overhead, the fullest expression of spatial polarity, we can quell or summon emotional tides, deepen our resolve, and even recalibrate our moral compass.

Sky is such a fixture in human neurobiology that multiple cortical areas in the brain keep track, map, and use its spatial canvas as a contextual cue to store and retrieve memories. Furthermore, our body’ gravitational orientation would be meaningless without the zenith and the horizon line. While the zenith establishes overhead vertical expansion, the visible horizon line––the distant divide between land and sky or sea and sky––is the horizontal plane perceived through the eyes of the observer.

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The High Steppe Desert, Oregon. Photo from Enter Space collection by Bill Witherspoon.

Yet, even if the zenith is the axis mundi of our perceptual world: can it be tampered with?

Could we isolate the sky’s zenith in such a way that rather than anchor our perceptual world, it unmoors us from its cardinal influence?

Surprised as you may be, the answer is: yes. We can.

The Sky’s Zenith: Axis Mundi––Unmoored

American artist James Turrell’s Skyscape installations are the proof in the perceptual pudding. For over half a century, Turrell has explored light as an abstract medium, engaging viewers with the malleability and limits of human perception.

Turrell’s training in perceptual psychology and his experience as an avid pilot led him to explore the conditions under which sensory perception, when lacking the usual contextual cues necessary to position our body in space, leads to a surge of perceptual artifacts.

For example, by generating Ganzfeld effects in his art works, viewers exposed to undifferentiated and uniform fields of color are unable to map out the space around their body. The disconcerting effect of featureless, color-saturated spatial fields lead the observer to experience perceptual disorientation and outright hallucination.

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Los Angeles County Museum of Art.

In Turrell’s Light Reignfall exhibit (2016), part of the Ganzfeld series, the Los Angeles County Museum of Art (LACMA) requested that visitors first sign a liability waiver before entering the artist’s “perceptual cell,” a precaution against an unexpected reaction someone might experience once inside the sealed fiberglass and steel sphere.

One at a time, unfazed visitors, wearing noise cancelling headphones and lying supine on a narrow bed, are inserted through the chamber’s small opening in a manner much akin to the experience of entering the scanner bore of diagnostic imaging equipment.

Once inside, a person’s peripheral vision is surrounded by the glow of neon blue light. The hatch closes and the installation technician begins a 12-minute cycle of pulsating strobe lights in saturated ambient colors––Blue…Green…Magenta…Amber––that embrace the observer in an eerie visual fog. (Learn more about the Light Reignfall exhibit.)

The captive observer’s focal and peripheral vision is unable to spot an edge, a textured surface, or even a seam that would reveal the spherical chamber’s true size. This leads most visitors to experience a disembodied vastness, a strange sense of corporeal drift that is reported to be unlike anything one can relate to or recall experiencing.

For many, the perceptual cell’s frenzy of pulsating light yields a psychedelic kaleidoscope of rhythmic, vibrating geometrical shapes. Often, music seems present and shapes appear in a contrasting hue to the predominant ambient color––morphing, blending, and dissipating at various rates. Thus, the liquid morphogenesis appears to flash at an indeterminate distance that can never quite be pinpointed.

The real kicker is that, as time passes and the visual spectacle speeds up becoming audio-visual, viewers are unable to ascertain whether this exotic, multisensory imaginarium is a function of the programmed rhythmic patterns of light or is emerging out of the brain’s own perceptual confabulations––dynamic, geometric hallucinations––for art’s sake.

A veritable, multisensory Twilight Zone, Turrell succeeds in whisking the observer to the limits of cognitive perception.

In other equally daring exhibits, Turrell succeeds in unmooring the zenith from everyday experience, stripping it of its axial prowess to turning it into a disembodied daylight discus––pure, abstract color.

One of his most lasting series featuring the zenith as pure light can be experienced in the more than the 80 Skyscapes he has designed around the world, ranging from Arizona to Zouz, in the Swiss Alps.

Piz Uter Skyscape in Zouz, Switzerland. Photo: Anna Roduit.
Piz Uter Skyscape in Zouz, Switzerland. Photo: Anna Roduit.

These chambers fill with bright color, always in sharp contrast to the perceived zenith––green surrounding deep blue, red engulfing light blue, purple encircling rose––to the point where the zenith is but a flat embryonic circle of light surrounded by an aureole of scintillating color; pure form hovering overhead.

According to the artist’s web site, Turrell’s medium is pure light. He says: “My work has no object, no image and no focus. With no object, no image and no focus, what are you looking at? You are looking at you looking. What is important to me is to create an experience of wordless thought.”

One could argue that, by definition, an image is wordless thought and that even light devoid of context as Turrell is driven to stage, involves external stimuli, which implies both a focus and an object (a visual field). But not to quibble with the artist or his intentions, the fact is Turrell succeeds in presenting light to the eye and brain of the observer so far removed from its common contexts that it becomes an otherworldly presence: pure space stripped down to essential luminescence.

If an artist can frame the zenith to generate a spatial experience of axial disembodiment, can the opposite perceptual feat be manufactured? Can we create an illusory celestial zenith leveraging bedrock knowledge of our hard-wired habits of perception, masterful composition, and identifiable image and light?

In other words, can the adept illusionist anchor the occupant––one who is captive in an isolated interior space––to the heavenly zenith? Can we construe the proper point-of-view for an observer with no visual access to the sky and effectively alter her experience to such a degree that she perceives a meaningful connection to the heavens?

In this reverse case, the answer is also affirmative. We can.

The Sky’s Zenith: Axis Mundi––Restoring the Unmoored

Unlike James Turrell, an avid pilot with over twelve thousand hours of logged flight time, American visual artist Bill Witherspoon stays on the ground. Still, both men’s artistic pursuits have been equal parts solitary and dogged: Turrell, high and far in the heavens, to Witherspoon’s wily and earthbound remoteness.

Bill’s approach to experiencing the vastness of the sky and its ability to modulate perception initially rested on inhabiting one of the most solitary and geologically interesting places on the Pacific Northwest: the Oregon High Desert.

Rather than flying off into the ether, Witherspoon drove into the heart of the desert with nothing more than a 92’ square-foot studio pulled by a 4X4 pickup.

Main image 52 kilometers (32 miles) over Bill's truck and studio. Inset 1,910m. (6,265 ft.) above ground.
Main image 52 kilometers (32 miles) over Bill’s truck and studio. Inset 1,910m. (6,265 ft.) above ground.

Undisturbed by civilization and rarely coming into contact with another human being, Bill could spend time in undisturbed nature. With the sky’s celestial canopy dwarfing everything around him, both human and artistic perception, as well as scale and perspective, expand until one sees more deeply into the way nature works.

It was here, in the high desert, that Bill first had the idea to switch from painting the sky with watercolors to exploring the capabilities of digital photography to capture large swaths of the sky and faithfully reproduce them on illuminated ceiling panels.

Since he sought to reproduce the zenith, not as symbolic image, but as a perceived axial element in an enclosed interior, he understood that staging a spatial illusion would require a closer study of the mechanics of visual perception, as well as a deeper understanding of our brain’s reaction to both contextual and structural cues.

James Turrell Twilight Epiphany Skyscape, Moody Center for the Arts, Rice University. Photo: Cameron Durham.
James Turrell Twilight Epiphany Skyscape, Moody Center for the Arts, Rice University. Photo: Cameron Durham.

Unlike Turrell, whose luminous spatial canvass are bereft of contextual cues and expose the invisible matrix of human perception, Witherspoon sought to mine our hardwired, embodied memories of gazing up at the sky to conjure a powerful (and healing) illusion. Bill sought to generate an experience that would satisfy our need to feel connected to the sky, even in the artificial and isolated confines of a hospital or interior office.

Confident in his experience out in the High Steppe desert that an unencumbered celestial zenith attunes the observer to the deepest undercurrent of life, he set out to reproduce the visceral catharsis brought about by those environmental conditions.

The project would require proficiency in multiple skillsets. First, it required technical skill to faithfully reproduce the sky images, first from 4×5 film and then from a sophisticated 80 Megapixel digital camera and a graphics software system. The main challenge involved faithfully calibrating the sky’s blue luminescence as images are transformed from RGB files to CYMK printed films adhered to a transparent media, backlit by T5 lighting systems, and later by back or edge-lit 6500K LEDs.

Photo from "Enter Space" collection by Bill Witherspoon.
Photo from “Enter Space” collection by Bill Witherspoon.

Second, it required technical know-how in LED binning standards to generate flawless white light of a specific color temperature (6500K), which would then bring to life the rich saturation and subtle hues of printed and transparent high altitude skies. However, the perceived depth experienced by the observer of these calibrated image panels (SkyTiles) was achieved due to a third essential feature of the photography: its compositional attributes.

The Open Sky Compositions that Bill first put together were both the result of his long experience observing the sky under diverse year-round conditions. The universal cognitive effects the sky had on his experience living out in the desert convinced him that it was possible to elicit a similar response in an observer in a completely enclosed interior environment.

However, to succeed, he would have to use compositional elements in the sky image to record the pertinent sensory cues that gave rise to the experience of vastness. In order to do this, Bill not only had to embed compositional elements within the sky image, he also had to add a fourth and final component: contextual and structural cues.

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Aperture SkyCeiling, 2020 Architizer A+ Popular Choice Award, Contract Ceilings category.

It was not enough to backlight the sky image or imbue it with a realistic composition that would trigger our biophilic memories of looking up at the sky. The image had to be realistically wedded to the rest of the interior envelope, specifically the ceiling plane, of a variety of interior environments.

Aware of the power of context to alter the way our brain interprets sensory input, Bill enhanced the visual illusion of sky by incorporating structural cues in plain sight. He added a faux skylight framework around the image panels that casual observers could identify as a genuine skylight framework.

Given that the casual observer hardly glances at interior ceiling structures, the perimeter, which also serves to raise the image tiles away from the rest of the ceiling, had the subtle effect of lending the illusory sky a vertical presence beyond the palpable borders of the faux skylight framework.

The result was a convincing illusion of proximity to a wide-open blue sky. With more and more Luminous SkyCeiling installations under his belt, Bill began to recognize a familiar experience in patients exposed to the illusory skies and in the clinical staff working under their influence. As more hospitals called to order these visual illusions of nature, his curiosity increased.

Image 9 Custom Sky Ceiling

One patient’s experience in particular stands out. It was relayed to Bill by the head of nursing at a women’s oncology treatment center in Indiana. After her PET scan was completed, the staff ushered the patient to the changing area outside of the imaging suite.

The room, small and featureless beyond a lone chair and lamp, plus a narrow closet to hang one’s clothes, was designed for expediency, nothing more. Yet, when the nurse did not see the woman come out after a few minutes, she gently knocked, and reminded the patient that her scan was complete, that she could get dressed.

The woman replied that she knew. However, she said that the room had such a peaceful and spiritual feeling that she wanted to remain inside a little longer. The nurse acquiesced and let her take her time.

It wasn’t until after the woman left that the nurse realized that the changing room had recently been outfitted with a 4’ X 6’ Luminous SkyCeiling––a view of wide open sky and blossoming black locust trees directly overhead.

The small changing room, claustrophobic and sparse, now appeared to have become a refuge that invited quiet introspection. It made enough of an impression that she shared the story with Bill. Other stories recounted similar kinds of experience. Curious to learn more about the internal process by which the vastness of the sky impacts cognitive perception, physiology, and psychology, Bill enlisted the help of a team of researchers, including a neuroscientist, an environmental psychologist, and an architect, to peer into the neural correlates of illusory skies.

The results of the published, peer-reviewed study found that subjects exposed to the bi-sensory illusory skies, which generate both visual and spatial cues, uniquely engage areas of the brain involved in depth perception and spatial cognition.

In other words, environmental designers can expose subjects to an illusory architectural portal that depicts a realistic perceived zenith, thereby altering their visceral experience of interior space. In enclosed or isolated interiors, the captive and casual observer is able to reestablish a perceived proximity to the sky’s vastness through a bi-sensory illusion, thereby triggering the autonomic Relaxation Response.

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These realistic architectural illusions trigger pre-cognitive reactions in the observer that facilitate the autonomic relaxation response and enable occupants to feel at ease in otherwise isolated or highly artificial interiors. A 2015 study conducted by Texas Tech University and Covenant Health in a surgical in-patient hospital found that patients assigned to rooms with an illusory sky, 24-sq. ft. Luminous SkyCeiling, reported 50% less acute stress and 34% less anxiety, than patients in rooms without the illusory sky.

Perhaps the most impressive aspect of the Texas Tech University study was that it was carried out in a patient ward where both the control and experimental rooms had large window views to the outside. The results of the study underscore the restorative significance of the illusory zenith in the environmental design of clinical spaces as opposed to the mere presence of daylight through window views.

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Thus, these veritable, multisensory portals to open sky, albeit an architectural conceit, become a cognitive and visceral reality for the observer.

Once again, the artist succeeds in recording the vastness of his desert experience in the brain’s neural networks that recognize spatial maps and trigger our biophilic memory of open skies. By generating a meaningful zenith illusion in enclosed interior environments thousands of miles away from the real desert sky, the artist reveals that there is an intimate connection between what we see and what we remember. Hence, what we experience is a dynamic function of externalizing our mind as well as internalizing the world.

The restorative and therapeutic benefits of bone fide illusory skies have since been presented at leading conferences on healthcare and architectural design, including the Academy of Neuroscience for Architecture while the published Texas Tech University fMRI study has earned awards from the Environmental Design Research Association (EDRA) and International Academy for Design & Health.

Epilogue: of Sight & Perception

George Inness, one of the most influential American landscape painters of the 19th Century, sought to demonstrate, through his paintings, the reality of the unseen, as well as the connection of the visible with the invisible. These themes are both present in the craftsmanship and aesthetics of James Turrell’s Skyscapes and Sky Factory’s Luminous SkyCeilings.

While James Turrell’s lifelong research in visual and psychological perception carries on in the topography of Northern Arizona’s Painted Desert with his ambitious Roden Crater project, Sky Factory’s research into the neuro-architecture of sky illusions continues to uncover finer layers in the mechanics of visual perception.

Sky Factory artists and engineers continue to refine ways to deliver more realistic illusions of sky. Rather than erase the contextual cues necessary for our senses and cortical areas to recognize the sky’s zenith, as Turrell’s Skyscape chambers skillfully do, the design framework behind Sky Factory’s Open Sky Compositions, do the opposite.

The company’s latest generation of bi-sensory sky illusions––Aperture SkyCeilings––deepens the illusion by including a strategically placed interstice between the image panel and the trim perimeter that cannot be explained by customary architectural details. While the mechanics that produce the gap are hidden from view, the gap itself is seen as an incomprehensible detail that triggers a remembered perception.

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Aperture SkyCeiling’s imperceptible interstice deepens the illusion of depth.

This spatial memory both counters and folds the external reality of the flat sky image into the sensible, cognitive reality of our experience: an open oculus to the zenith.

The unexpected interstice between the trim perimeter and image tile dissociates the skylight framework, the tangible architectural component, from the sky image in a surreptitious manner, thereby yielding a visceral relaxation response that we associate with pleasurable contemplation. In this way, the Aperture’s interstice, along with its grid-free, non-reflective planar surface, delivers a still more convincing illusion of perceived zenith and vertical vastness.

The result achieved by the Aperture’s interstice, (produced by an unseen mechanical wall), along with its grid-free, non-reflective planar surface is a more realistic illusion of perceived zenith and vertical vastness.

Also interesting to note is that the product’s graceful opening also captures the look and feel of Turrell’s much larger Skyscape portals while explicitly designed to precipitate the exact opposite perceptual effect.

We are unmoored by experiencing Turrell’s art, in spite of what we actually see. Conversely, Sky Factory uses the art of illusion to moor us back to an experiential reality we cannot actually see.

Looking up at the sky’s zenith, one cannot help but wonder:

Where does human perception begin and the world end?

 “The true use of art is, first, to cultivate the artist’s own spiritual nature.”

                                                                        ––George Inness, American Landscape Painter (1825 – 1894)