Allyson Bieryla, an astronomy lab and telescope manager at Harvard, will operate the Arduino from Jackson Hole, Wyoming, inside the path of totality. She will stream the audio on a website online, which Diaz Merced will open on her computer in Cape Town.

So far, Bieryla says, “the real challenge has been trying to find a light sensor that’s sensitive enough to get the variation in the eclipse.” In totality, the sun will appear about as bright as a full moon at midnight. The team has tested the Arduino at night, under the moonlight, to make sure it can pick up the faint luminosity.

Diaz Merced, a postdoctoral fellow at the Office of Astronomy for Development in South Africa, was diagnosed with diabetes as a child. In her early 20s, when she was studying physics at the University of Puerto Rico, she was diagnosed with diabetic retinopathy, a complication of the disease that destroys blood vessels in the retina. Her vision began to deteriorate, and a failed laser surgery damaged her retinas further, she said. By her late 20s, she was almost completely blind. She recalls watching a partial solar eclipse in 1998 in Puerto Rico, when she still had some sight.

“I was able to experience the wonderfulness—of the sun being dark, of having a black ball in the sky,” she said. “That is why it is important to use the sound in order to bring an experience that will bring that same feeling to people who do not see or are not visually oriented.”

While Diaz Merced experiences the eclipse from a classroom in Cape Town, Tim Doucette will observe the event at a campground in Nebraska, smack-dab in the path of totality. Doucette is a computer programmer by day and an amateur astronomer by night. He runs a small observatory, Deep Sky Eye Observatory, near his home in Nova Scotia in a sparsely populated area known for low light pollution and star-studded night skies.

Doucette is legally blind, and has about 10 percent of his eyesight. He had cataracts as a baby, a condition that clouds the lenses of the eye. To treat the disease, doctors surgically removed the lenses, leaving Doucette without the capacity to filter out certain wavelengths. His eyes are sensitive to ultraviolet light, and he wears sunglasses during the day to protect his retinas. Without shades, Doucette said he can’t keep his eye open in the brightness of day. But at night, his sensitivity becomes an advantage. With the help of a telescope, Doucette can see the light coming from stars and other objects in the sky better than most people.

“My whole life, I’ve always been asking people for help, saying, ‘hey, what do you see?’” Doucette said. “When I stargaze with people, the tables are reversed.”

Doucette sees best at night, safe from the glare of the sun. He uses starlight to guide him during the short walk from his observatory to his home. “When I’m walking down the road, especially during the summer months, the Milky Way is just this incredible painting going from north to south,” he said. “It’s millions and millions of points of light. It’s like a tapestry of diamonds against a velvety background.”