22.10.2021

New Telescope “Gives Back the Sky” to City-Dwellers

Any astronomy buff will tell you about the first time they looked through a telescope. What many of them won’t say, though, is how disappointing those first looks can be. I remember my own all too well, from when I was a boy. It was a glimpse from my suburban front yard of the majestic stellar nursery we call the Orion Nebula, hard-won after close to an hour of setting up, pointing and focusing a modest refractor telescope my father had purchased at a department store. Through the eyepiece, the nebula didn’t look at all like the crisp, colorful images I had seen in books and magazines. Instead, it was a gray smudge, easily mistaken for a wisp of cirrus cloud, its faint light washed out against the blue glare of a nearby mercury–vapor streetlamp. After that, the telescope just gathered dust-and with it, most of my desire to delve deeper into amateur astronomy.

At least that was the case until last month, when I tried a new sort of telescope at a stargazing party in a secluded spot of the sprawling Evergreens Cemetery in Brooklyn. Set up alongside several standard consumer models, the SETI Institute astronomer Franck Marchis is offering demonstrations of a prototype “Enhanced Vision Telescope” produced by the small French start-up Unistellar, where he also works as Chief Scientific Officer. Marchis is best known as the discoverer of multiple asteroids, and for coaxing remarkable observations from modest ground-based telescopes. He was the first to capture images of volcanic eruptions on Jupiter’s moon, Io, without the aid of space telescopes or interplanetary probes, and is part of a vanguard of astronomers developing new technologies for imaging planets orbiting other stars. This night, however, he is merely serving as a celestial evangelist.

“What happened to you is what happens to almost everybody when they use a telescope to look at anything besides the moon and some of the planets,” Marchis says when I tell him about my childhood experience. “You invest hundreds of dollars, you maybe drive far to get away from city lights, and you spend hours trying to align and calibrate your telescope to observe a galaxy or a nebula. You might think you’ll see something like a pretty picture from the Hubble Space Telescope. But what you get is a blurry dot to show your kids or your wife or your partner, and they’re disappointed. And then they’re done!”

Marchis traces his own interest in astronomy to a late night of boyhood bonding with his father in the French countryside, watching without a telescope as the Earth’s shadow tinted the full moon red during a lunar eclipse. It was “the first moment in my life where I felt things were really happening in the sky,” he says, “where I realized we are on this small rock we call Earth orbiting a star, and that there must be countless other worlds around all the other stars out there.” Not long after, Marchis would be stargazing more seriously, staring at the rings of Saturn through his first telescope.

Called the “eVscope” (pronounced Ee-Vee Scope) for short, Unistellar’s product outwardly appears to be just a typical 4.5-inch Newtonian reflector-a simple small telescope that, along with its tripod, easily fits inside a backpack. But a peek through its eyepiece reveals the eVscope’s power: Using a proprietary system of sensors, optics and specialized software, the telescope can amplify and display the accumulated light from a faint target over time, stacking up and processing hundreds of images to correct for instrumental jitter and smeared exposures to build up vivid, sharp views that rival those from far larger and more expensive equipment. And, as Marchis intends to show with his demonstration from a Brooklyn graveyard, the technology even works under poor viewing conditions-such as in and around New York City, where the glare of city lights is so oppressive that even on clear nights one can practically count on fingers and toes all the stars visible to the naked eye. (The technology works so well, in fact, that Unistellar’s eVscope has managed to capture and display images of faraway Pluto in its eyepiece as a dim and distant dot hanging in the light-polluted skies over Marseilles, France, and San Francisco.)

“Remember, this telescope isn’t just about pretty pictures,” Marchis says. “It could also lead to new ways of doing science.” According to Marchis, by the time the eVscope hits stores it should be capable of imaging objects as faint as about 15 apparent magnitude-that is, as faint in Earth’s skies as a 100-watt lightbulb seen from 30,000 kilometers away. That would, among other things, allow it to image, track and study tens of thousands of known asteroids, and to discover new ones as well. Through a partnership with the SETI Institute, eVscope users will have the option of automatically uploading their observations to an online database for use by amateur and professional astronomers alike. “We’ll build it up slowly, with a thousand eVscopes providing millions of frames for any given region of sky that can be combined to get good signal to noise,” Marchis says. “We could use it to search for Earth-threatening asteroids and comets, stellar occultations, supernovae, variable stars; maybe even things we can scarcely imagine-a flash of light, a laser pulse from another cosmic civilization? Who knows what we might find-it’s not like we have been observing the sky continuously at these magnitudes.”

To aid the acquisition and construction of that database, Unistellar is developing a semiautonomous “Field Recognition System” for the eVscope that uses GPS data to help point the telescope and identify objects of interest. That system, though, is not yet fully integrated into the prototype; during the demonstration Marchis guides the eVscope by hand, navigating with the help of an app on his smartphone.

Before being cut short by encroaching clouds, his demo reaches its zenith with a view of the Ring Nebula, a one-light-year–wide shell of gas cast off from a dying star about 2,000 light-years from Earth. After zooming in on the nebula’s celestial coordinates, Marchis toggles the telescope’s enhanced light-amplification mode, and steps back to let me look through the eyepiece. Within seconds, the nebula materializes from a glittering field of background stars like a polished disk of turquoise and coral nestled in black, diamond-studded velvet. The colors come from ionized nitrogen, hydrogen, oxygen and other gases that had once been in the dying star’s atmosphere-and probably in some accompanying planets, too-now stripped away and set aglow by intense ultraviolet light from the star’s slowly cooling white-hot core. A bit more than five billion years from now, astronomers guess, our sun and solar system will experience a similar fate. One by one, the other stargazers line up to peer at the stellar memento mori. A few even take out their smartphones to snap pictures of the nebula through the eyepiece.

Steps away, another telescope more than twice as large as Unistellar’s is also trained on the Ring Nebula. Through its excellent but old-fashioned optics, the nebula appears as a vaguely doughnut-shaped gray mist against a background of pale stars. Like many faint sky objects, here it is best seen indirectly, slipping into invisibility when focused on and only appearing again out of the corner of the eye, as its trickles of photons fall on the retina’s more light-sensitive edges rather than its more color-sensitive center. The difference is striking, and illustrative of why galaxies and other deep-sky objects can be so problematic to appreciate through ordinary telescopes. The nebula’s vivid hues are there waiting to be seen, hidden due to the inherent limitations of the human eye. Paired with digital camera, a motorized star tracker and a laptop running imaging-processing software, any telescope could deliver a serviceable colorful image of the Ring Nebula in a matter of minutes-but not in a real-time glance through an eyepiece.

“There is no magic in what we are doing,” Marchis says later, noting that high-powered amateur astronomers at past Unistellar events have replicated many of the eVscope’s feats, albeit with much more (and far pricier) equipment and greater effort. “We are taking the technology that professional astronomers have been using for years, and integrating it into a small, affordable telescope that anyone can use. The eVscope is meant to be equivalent to a smartphone, but for astronomy.”

The company, Marchis says, hopes to bring the eVscope to market in fall 2018, at a price point similar to the latest iPhone or a mid-tier laptop. But, of course, he and others at Unistellar say they aren’t making enhanced-vision telescopes for the money. Rather, they are trying to restore something they feel people-particularly those in bustling, starlight-starved cities-are at risk of losing: A connection with the heavens above.

“As an astronomer, I’m biased, of course, but it does matter, being able to see the stars,” Marchis says after his demonstration ends. “When people lose that, they forget where they really are. They forget that they live on a tiny planet around a little star in a huge galaxy, and that we as human beings are more than a bunch of apes who want to buy fancy new cars or the latest Apple phone. We are part of a bigger picture. It’s a big moment in your life, when you see and feel that for the first time. Exploring the entire universe can start with something tiny, like looking through a telescope. That’s what happened to me when I saw my first eclipse with my father. Maybe we can make it happen for today’s kids, too. For everyone. We want to give back the sky.”

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