The Best Night Vision Goggles $30,000 Can Buy

Just the tech you’ll need to execute covert

nighttime operations — such as a midnight ride on an illicit trail

It started over a backyard beer. We were in Marin, just north of the Golden Gate Bridge, enjoying a sunny afternoon and a view of Mount Tamalpais. I was thinking out loud, brainstorming with a newly made acquaintance, and a bit too far into my cups. “Why not mountain bike the entire Pacific Crest Trail,” I asked, “all the way from Mexico to Canada?” I’m no mountain biker, but my livelihood as a writer depends on finding adventures, and then writing about them. “No problem! Completely do-able,” replied Zander, whose last name must remain anonymous for reasons that will soon become clear, “except for where the PCT cuts through Yosemite Valley.” Strictly speaking, the entire 2,663-mile long trail, widely known by its acronym, is off-limits to mountain bikers, but Yosemite’s trails are patrolled.

Spreading out a USGS topo map, he calls my attention to the problematic stretch through Yosemite, 42 miles between Devils Postpile and Glen Aulin. His thick finger points to where the PCT cuts through Tuolumne Meadows, the largest campground outside of the valley, complete with RV hook-ups, post office and general store. “Rangers everywhere,” he says, pausing for a long moment of contemplation. “The only way to get through,” he decides, suddenly brightening, “is with night vision.”

Marin is a funny place, full of contradictions. On one hand, there’s an unmistakable hippie vibe. Earth shoes and hot tubs are (still) the order of the day. Yet it’s now the richest county in California, and with great wealth come great egos. Scratch the laid-back and bohemian surface, and a righteous, authoritarian streak can emerge. Marin’s great cultural claim to fame, mountain biking, is a perfect example. Mount Tam, which pushes the center of the county up like a tentpole, is where the sport was invented in the ’70s. But after vehement backlash from hikers and equestrians in the ’80s and ’90s, most of the single-track trails on the mountain are now off-limits to bikes. Mountain bikers have become a persecuted minority in their ancestral homeland.

Forty-something years old, Zander embodies the sort of contradictions that define the place. By day he’s a buttoned-up engineer of some repute. By night he’s an outlaw, going to great lengths to steal the forbidden single-track on Mt. Tam. At least two evenings each week for nearly 20 years, he and a few like-minded friends have been riding Mt. Tam at night, illuminating the trails with lights that they build themselves. The first models were hacked together from junkyard parts: a headlight up front and a car battery strapped to the rear rack. Early efforts used incandescent bulbs, then halogen, then high intensity discharge arc-lights. Then, 10 years ago, a German company called Lupine released the first truly usable LED-based bike lighting system, and the number of night riders exploded.

On a clear night in Marin, one can look up at Mt. Tam and pick the night riders out, plainly visible as twinkling lights whooshing down the side of the mountain. It’s a trick that local authorities have discovered as well. One Wednesday evening not that long ago, Zander and his buddies pushed off from the top of Mt. Tam and found themselves face to face with Marin’s finest at the bottom. They got off with a warning. “That’s when I started to wonder about advanced night vision,” Zander says.

As a technology, the night vision goggles are pretty easy to grok. One is simply looking through a viewfinder at a video feed piped in from a special camera — one vastly more sensitive to light than is the human eye. Ambient light — from the moon, from the stars, even from the faint airglow of the upper atmosphere — is amplified so that one can see in the dark. It’s the video equivalent of turning up the gain on a mike.

But there is high gain, and then there is high gain: whereas a typical “Gen 1” system might amplify the ambient light by a factor of a thousand, the super-advanced “Gen 3” systems can reach amplification factors 50 times higher. One can find Gen 1-style night vision goggles on Amazon for as little as $300. In contrast, a good Gen 3 system costs a hundred times as much — and, by law, you need to be a US citizen in order to even look through the eyepiece.

The irony is that both versions, the Gen 1 and the Gen 3 (as well as the intermediate grade, sensibly known as “Gen 2”), are all analog technologies. The rest of the camera world has long since gone digital, but night vision is the last stand of a technology that has been around since Edison’s time. All night vision is built around the same core technology: the vacuum tube — specifically a video camera tube. Those are the tubes that TV (and then video) cameras used before the technology all went digital. Video camera tubes, as it turns out, make the best light amplifiers.

First, a dim nighttime image gets focused onto the front of a video tube, which is covered in a photosensitive chemical. The chemical absorbs the light and spits out electrons into the vacuum of the tube. (This is Einstein’s famous photoelectric effect, for which he won a Nobel in 1921.) So far, so good: this is how all tube-based video cameras work. Once inside, the electrons are accelerated and focused by means of a high voltage and, in the case of advanced night vision, through a very thin slice of a very thick bundle of optical fibers. As the highly charged electrons stream through the fibers they invariably bounce off their walls, knocking free more electrons — and multiplying the original signal.

Each of those fibers is essentially a pixel in the now-bright nighttime image that gets transmitted to the back end of the tube. There we have Einstein’s photoelectric effect again — but operating in reverse. The back of the tube is typically painted with a green phosphor, a chemical that absorbs incoming electrons and re-emits the energy as photons. That chemical is typically the same green phosphor used in old-fashioned monochrome CRTs — the source of night vision’s signature greenish glow.

To poach mountain bike trails it was clear, to Zander anyway, that no commercially available night vision was going to cut it. Not only are conventional goggles relatively dim, they also all cantilever the image intensification tubes in front of the user’s head — imagine a pair of binoculars strapped to your face. While useful for passive surveillance — hunting, perhaps — you can’t safely mountain bike with all that hardware dangling from your helmet.

What we needed was what the military’s Special Ops teams use: a design which takes the requisite hardware and folds it back around a soldier’s face. The O’Gara Group, a defense contractor based in Cincinnati, builds some of the very the best of these low-profile goggles. Each of their AN/PVS-21 Low Profile Night Vision Goggle helmets costs $30,000 and you can’t buy one without a security clearance. Stan Babb, the director of business development at O’Gara, jokes that he could tell me exactly who uses their AN/PVS-21, but if he did, he’d have to kill me.

Even so, Babb was nice enough to eventually hand over a test unit on the flimsiest of excuses: that I was a journalist, and I wanted to take the rig for a test drive. It was a five-month conversation, and along the way I had to prove that I was a US Citizen, and sign a document affirming that I would take a daily inventory of all equipment, because the technology is regulated by the Arms Export Control Act. I knew that O’Gara was serious about having me comply with the arms control act because only a few years before one of their competitors was caught sending the technology to China, and was fined $28 million.