You can dance among the planets, gaze at the Pleiades, maybe catch a moon transit behind Jupiter. But a backyard-viewable comet originating from beyond the realms of our sun? That was something the amateur community could only dream of, until a little world briefly came out of the darkness in 2017, before disappearing forever: 1I/ʻOumuamua.

The cigar-shaped object, our first confirmed visitor to the solar system, was far too faint for amateur telescopes. But like many other things in astronomy, you just need to give it time, and technology. After eight years, there's a network of telescopes poised to capture unprecedented views of a freshly found object on its own one-way trip through our solar system: 3I/ATLAS.

3I/ATLAS, as the name suggests, is just the third interstellar object scientists have confirmed. While 1I/ʻOumuamua came much closer to Earth than 3I/ATLAS will, luckily for amateurs this newer visitor is considerably brighter. And the Unistellar community of telescope observers is already seeing strange things. Unistellar is a French manufacturer of networked telescopes that allow backyard skywatchers to observe astronomical objects in detail at a low cost.

said Ariel Graykowski, a postdoctoral fellow at the SETI Institute who specializes in small bodies and who is coordinating the Unistellar group. "But we are seeing a lot of other stuff," she continued. 

Comets like 3I/ATLAS are thought to contain the building blocks of planets and moons, which includes water in some cases. But as of results made public in late August, SPHEREx — a NASA astrophysics-focused space observatory — spotted a bunch of carbon dioxide in the comet's coma, or atmosphere. 

Scientists are still trying to figure out why the water signature is more muted in 3I/ATLAS than comparable ones from the solar system. But generally speaking, what we are seeing is providing us a glimpse of the conditions under which this interstellar object formed. And for the bigger questions scientists and all of us have — how life arose, what faraway worlds may host in terms of environments — an interstellar object allows us to learn these things from no further than our own backyards. 

Graykowski has been working with the company Unistellar since she joined the SETI Institute, shortly after graduating in 2022. She says users of its commercial telescopes run the gamut — from retirees, to parents willing to fund their children's science, to enthusiastic midlife amateurs.

The price of one of these telescopes — typically a few thousand, depending on options you choose — is certainly not within reach of everybody. But that price point is similar to an overseas trip, an upgrade on a car, or a home renovation for more financially fortunate people willing to make different life choices in pursuit of backyard astronomy.

With the right amount of time and money, the Unistellar network of citizen scientists is literally doing just that — science. For example: they observed the breakup of another solar system comet, ATLAS, in April 2020. More recently, a paper in the Planetary Science Journal was published Sept. 25 based on their observations of activity in a comet named 103P/Hartley 2.

While amateurs do not necessarily have the experience of their professionally trained counterparts, with their status comes some perks: exclusive telescope time, and more flexibility to shift with weather and schedules. Much more than professionals who must adhere to a schedule on more powerful, high-demand telescopes regardless of the clouds overhead.

Wataru Ono, based in Japan, told Supercluster he initially participated because he wanted to contribute to planetary defense research. "I've since become interested in other programs as well, including comets," he said. "I believe one of the charms of this citizen science program is this personal domino effect — where one thing sparks interest in something else."

Margaret Loose, from New Mexico, joined four years ago out of simple love of the game: "I got into astronomy because it makes my eyes roll back in my head," she said. But as she got to know the others in the Unistellar community, she said she enjoyed parts of it that are related to science. "I really like having specific tasks to do. I like seeing the results come in, and I really like the international collaboration."

To be sure, no single company has a monopoly on helping amateurs observe 3I/ATLAS. Shadow the Scientists, an initiative based at the University of California, Santa Cruz, is hosting regular livestreams on various professional telescopes, letting anyone who joins watch the object in real time. 

The citizen science website Zooniverse has 3I/ATLAS photos on its "Rubin Comet Chasers" website, which parses photos from the National Science Foundation's and Department of Energy's Vera C. Rubin Observatory.

If you'd rather look at the object yourself, that's totally possible as well — with the right equipment or connections. You can try begging or borrowing from a local astronomy group, or using a museum's telescope if you're lucky enough to be nearby to one. Some folks are booking time on Internet telescopes. 

Others are readying to use their own telescope, as by its closest approach in early November, 3I/ATLAS is predicted to be at magnitude 11. The popular eight-inch Dobsonian telescope type, for example, will likely see the object easily in dark-sky conditions. (That said, do your research before buying — telescope purchases are far too complicated to offer recommendations)

Graykowski noted that one advantage of a network like Unistellar over these other options, however, is allowing folks all over the world to collaborate real-time as events unfold. For example, 3I/ATLAS may undergo "outbursts" — periods of higher activity — which could last only minutes or hours. Statistically speaking, you're more likely to catch such an event if many people are looking together in different locations at the same time.

Then there is also the community cheer that collaboration brings. Ono emphasized that the point of observing is not to appear in a scientific paper, or even to see something novel. "Not every scientific conclusion is a 'success,' " he said, "but I believe that experiencing the ups and downs of such outcomes sparks lively discussions within the community, making it more engaging."

There's also the knowledge among the observers that this object is more than a once-in-a-lifetime observation, like Halley's Comet, which keeps the amateurs going at long nights in front of their telescopes. 

"It's never going to happen again," Loose said. "Our species will ever see this object again."

....

Elizabeth Howell is a Canadian space journalist based in Ottawa.

More on 3I/ATLAS from NASA:

'Comet' 3I/ATLAS is the third known object from outside our solar system to be discovered passing through our celestial neighborhood. Astronomers have categorized this object as interstellar because of the hyperbolic shape of its orbital path. (It does not follow a closed orbital path about the Sun.) When the orbit of 3I/ATLAS is traced into the past, the comet clearly originates from outside our solar system.

Comet 3I/ATLAS poses no threat to Earth and will remain far away. The closest it will approach our planet is about 1.8 astronomical units (about 170 million miles, or 270 million kilometers). 3I/ATLAS will reach its closest point to the Sun around Oct. 30, 2025, at a distance of about 1.4 au (130 million miles, or 210 million kilometers) — just inside the orbit of Mars.

The interstellar comet’s size and physical properties are being investigated by astronomers around the world. 3I/ATLAS should remain visible to ground-based telescopes through September 2025, after which it will pass too close to the Sun to observe. It will reappear on the other side of the Sun by early December 2025, allowing for renewed observations.