Yes, and there are two ways to do it. CoeLux and Innerscene's Virtual Sun use optics to show a sun that looks infinitely far away and throw a sharp-edged patch of sunlight into the room; both are built into a ceiling void and sold through dealers. Sunday Light, the artificial skylight we make in London, makes sky light the way the atmosphere does, by Rayleigh scattering in a 120 cm sheet, and puts out 34,500 lumens so the whole room is lit like daylight. Most LED sky panels do neither: they show a sky colour on a flat surface.
What gives a fake sky away
Colour comes first. Innerscene puts a clear blue sky as high as 40,000K, far bluer than a 6500K daylight bulb, and direct sunlight near 5500K. A panel of evenly blue LEDs gets neither, so it reads as tinted plastic.
Then brightness. Indoors is 50 to 100 times dimmer than outdoors, and a sky that gives the room no more light than a ceiling light looks like a picture of a sky.
Then depth. Your eyes judge distance by focus, by the slightly different view each eye gets, and by how near things slide when you move your head while the sky stays put. A sky printed on a flat ceiling panel fails those tests within a step or two. Innerscene's comparison page sets the cues out in detail. The recessed systems are built to pass the depth test. Sunday is built to win on colour and brightness, from a fitting that hangs in the room rather than pretending to be a hole in it.
How CoeLux makes a sky and a sun
CoeLux, a spin-off of the University of Insubria in Italy, copies the atmosphere. Its sky is a thin transparent layer with nanoparticles dispersed through it, which CoeLux says reproduces the same quality and amount of Rayleigh scattering that sunlight undergoes crossing the atmosphere. The short blue wavelengths scatter sideways, so the layer glows blue. Behind it, high-brightness LEDs and lenses make a sun that your eyes focus at infinity, and that stays put as you move.
In the 45 HC, the sun's light leaves as a beam at 45 degrees and lands as a warm spot with defined edges, while the blue sky light tints the shadows, as it does outdoors. The datasheet gives a sky above 15,000K and a 3900K beam. The smaller LS Matte and HT25 have a softer sun that CoeLux calls slightly frosted.
How Innerscene makes it
Innerscene's Virtual Sun borrows from virtual reality. A headset puts a lens between your eye and a screen so the screen appears far away. Innerscene patented a way to combine many small images into one large display that does the same with nothing on your face.
Hundreds of LEDs make two kinds of light. A diffuse sky glow spreads across the room, and a sunbeam leaves at 30 degrees from vertical with 2.5 degrees of spread, which puts a bright rectangle on the floor or wall. Its sibling, Circadian Sky, has no sun: it uses double reflective glass so the surface reads as a window with depth behind it.
How LED sky panels make it
Consumer sky panels put tunable LEDs, with extra blue, behind a flat diffuser. Govee's Sky Ceiling Light adds a 478 nm sky-blue channel, and Philips Skylight uses blue-enriched LEDs that follow a day rhythm. Cheaper sky ceilings, such as the cloud panels sold for office grid ceilings, put a photograph of sky in front of a light box.
Both can look convincing in a photo, where the camera stands still. In the room the surface is flat and close, so your eyes focus on it and the clouds move with your head. They make good ceiling lights with a sky colour, at 1,400 to 7,000 lumens.
How Sunday Light makes it
The LED is at the bottom of the arm and shines up at the sheet. The sheet scatters the bluer light within it and reflects the warmer light. It's called Rayleigh scattering. It's what happens in the sky, and it's the effect CoeLux builds its sky on. You look up and see a sky glow with a warm sun-like centre. What you see in the sheet is real scattered sky light, not a picture of it.
Because the light comes off a sheet 120 cm across, the room gets soft, indirect brightness rather than a glare point. And there is a lot of it. A CoeLux 45 HC gives 4,100 lumens and a Virtual Sun 4,455. Sunday gives 34,500, which is 10,000 lux at 60 cm, in homes that mostly sit at 100-300 lux. Indoors is 50 to 100 times dimmer than outdoors, and closing that gap is most of what makes a room feel sunlit. How many lumens a room needs has the arithmetic.
On a schedule it follows the sun's colour, cool 6000K in the morning, then warmer and dimmer through the afternoon, and a CRI of 97+ keeps skin and wood looking as they do outdoors. It hangs like a chandelier, so there's no void to build, as artificial skylights that don't need a hole in the ceiling sets out. If CoeLux is the one you had in mind, CoeLux alternatives for a home compares the options side by side.
Sunday Light, our indoor sunlight ceiling light, is £5,900 in the UK, $6,900 in the US and €6,900 in Europe, with free worldwide delivery.
