Visiting Mauna Kea, the world's best spot for stargazing

Crave's Eric Mack recently trekked to the top of Hawaii's Mauna Kea volcano to visit one of the most advanced observatories on Earth, the "eyes of humanity" in the middle of the Pacific.

Eric Mack Contributing Editor
Eric Mack has been a CNET contributor since 2011. Eric and his family live 100% energy and water independent on his off-grid compound in the New Mexico desert. Eric uses his passion for writing about energy, renewables, science and climate to bring educational content to life on topics around the solar panel and deregulated energy industries. Eric helps consumers by demystifying solar, battery, renewable energy, energy choice concepts, and also reviews solar installers. Previously, Eric covered space, science, climate change and all things futuristic. His encrypted email for tips is ericcmack@protonmail.com.
Expertise Solar, solar storage, space, science, climate change, deregulated energy, DIY solar panels, DIY off-grid life projects. CNET's "Living off the Grid" series. https://www.cnet.com/feature/home/energy-and-utilities/living-off-the-grid/ Credentials
  • Finalist for the Nesta Tipping Point prize and a degree in broadcast journalism from the University of Missouri-Columbia.
Eric Mack
6 min read
The Keck telescopes use laser guide stars to capture images of distant galaxies almost unparalleled in their clarity on Earth. Daniel Birchall, Subaru Telescope/NASA

MAUNA KEA, Hawaii -- I was recently having lunch at a lovely and only slightly overpriced cafe overlooking the Pacific in the historic resort region of Kailua-Kona on the dry side of Hawaii's "Big Island" (the island itself is also named Hawaii). I hopped in a rental car and traveled 60 miles by road, ascending nearly 3 miles in elevation from the dry, breezy coast through thick clouds shedding rain and hail onto my windshield, and finally reemerged into sunshine in the last few miles of the journey as I approached the Mauna Kea observatory complex, a collection of more than a dozen advanced telescopes that arguably serve as the eyes of mankind.

As technology has advanced over the centuries, we've been able to look exponentially farther into the depths of the universe with each new generation of super-sophisticated telescopes and supporting stargazing instruments. But somewhat ironically, getting top performance out of this equipment has meant locating it in increasingly isolated and even extreme spots around the globe, like Spain's Canary Islands, Chile's Atacama Desert, or here, on top of a 13,800-foot dormant volcano in the middle of the Pacific Ocean that last erupted about 4,500 years ago.

The view of the Pacific, and of neighboring active volcano Mauna Loa, is blocked by the bank of clouds floating just a few hundred feet below the summit and creating a heavenly view of their own.

Stargazing at Hawaii's Mauna Kea (pictures)

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But I've come here to gaze upon the nearly-as-majestic manmade structures that dot the top of this volcanic cone, and two of the huge observatory domes in particular. Over the past few years, Crave has reported on the exponentially increasing number of discoveries of distant galaxies and potential exoplanets -- including some that may support life -- and, inevitably, at least some of the data behind many of those discoveries was collected by the two huge telescopes residing within those domes, better known as Keck I and Keck II.

Collectively known as the Keck Observatory, these two telescopes use huge segmented mirrors 10 meters (about 33 feet) across to reflect countless photons of light that have literally traveled from the other side of space and time. Since seeing first light in the 1990s, the Kecks have enjoyed a long reign as the biggest telescopes ever created; the light-collecting surface area of another notable telescope (known as the GRT) that began observations in 2009 in the Canary Islands is just a smidgen smaller than that of each Keck.

A more recent endorsement of Mauna Kea as the perfect spot for galaxy gazing is its selection as the future site of one of the next generation of surface telescopes, the gargantuan Thirty Meter Telescope that will sit near the current site of the Keck 'scopes. Simply known as TMT, the telescope would be like a super-size version of Keck, and is being developed with support from some of the same institutions (such as the University of California and Caltech) that currently help manage Keck.

Keck's Bob Goodrich. Eric Mack/CNET

In addition to their raw size, both Keck telescopes are equipped with laser guide star adaptive optics that help eliminate visual distortion from the Earth's atmosphere, creating images with clarity that rivals that of our most advanced space telescopes like Hubble, which don't have to worry about our pesky atmosphere distorting their view of the universe.

"I always explain that adaptive optics is very unromantic, because it takes the twinkle out of the stars," Bob Goodrich, Keck's head of nighttime operations, told me when I visited his office at the base of Mauna Kea in the charming town of Kamuela, which sits right on the dividing line of the wet and dry sides of the island. Fortunately, the Keck offices are just barely on the dry side of town, just as the Keck telescopes always seem to be just above the top edge of the clouds that frequently populate the skies around the volcano.

The romance-killing lasers he's describing basically serve to help measure the amount of distortion being caused by the atmosphere, data that is then fed into a computer and used to adjust images recorded by the telescopes accordingly to produce unparalleled clarity among Earth-based telescopes. Combine this technology with the fact that Keck's mirrors are much larger than Hubble's, and Keck is arguably the best set of eyes for tasks like spying deep into the universe, examining how galaxies form, and sussing out all those distant exoplanets.

"We're creating images that no one could see that sharply before, so you start to learn all sorts of interesting things," Goodrich said.

The top of Mauna Kea, with the dual Keck domes on the right. Eric Mack/CNET

He tells me Keck is one of the few places that can capture the spectra of planets, "which is really hard and takes a lot of attention to detail, but people in this field are really good at detail."

Using spectroscopy, and newer instruments at Keck like Mosfire (for "Multi-Object Spectrograph for Infrared Exploration") that can simultaneously record near-infrared spectra of multiple objects, astronomers here can more easily identify specific elements in distant galaxies -- like methane, one of the signposts of potential life, for example. Keck data can also help identify how fast an object might be moving toward or away from us, which is another way of "seeing" planets, Goodrich explains, by observing the gravitational pull and push of planets and stars upon each other.

The perfect vantage point
With so much high-tech precision at work, it would be a shame for it to be ruined by something that's much more difficult to control so precisely -- like clouds, bad weather, light pollution, and turbulent air.

Which is why it was thought to be worthwhile to build Keck at a cost of many millions of dollars, at the end of a rough road on top of a very tall volcano in the middle of the world's largest ocean. If you arrive on the Big Island at night, the first thing you'll notice is that the streetlights seem to be malfunctioning, giving off a strange yellow hue that's dimmer than your typical urban illumination. This particular shade is actually easier for the telescopes atop Mauna Kea to filter out, and reduces overall light pollution. Add to that the fact that cloud cover on top of the volcano only hinders observation less than 10 percent of the time and that the air moved across the Pacific by the trade winds is some of the cleanest and least turbulent on Earth, and it's easy to see why this is an ideal place to put the eyes of our species.

Oh, yeah, and did I mention all this is in Hawaii? Maybe you've heard of it -- the coffee alone is worth the trip.

But the discoveries this once-angry mountain will give us (the sensitive telescopes atop Mauna Kea would detect minute ground tilts that foretell a future eruption, according to the USGS' Hawaiian Volcano Observatory) are really just beginning. Ground breaking could begin as soon as later this year on Keck's new neighbor, TMT, and there is the potential for this next generation of observatories (others of similar size are also planned for installation in Chile in the coming years) to revolutionize our understanding of things like galaxy formation, the existence of life beyond our solar system, black holes, dark matter, and even the standard model of particle physics.

Atop this sleeping volcano we have installed the retinas of humanity, and with planned upgrades like TMT, the future up here is so bright, perhaps we need to start developing some specialized shades as well.

Updated at 1:50 p.m. to reflect that the Keck telescopes have slightly more light-collecting surface area than the newer "GRT" telescope in the Canary Islands.