The summit of Mauna Kea, the world's tallest mountain if measured from its base on the ocean floor, is the best place on earth for astronomical observations because its mid-Pacific site is near the equator and because it enjoys clear, pollution-free skies and pitch-black nights with no urban light to interfere. That's why Mauna Kea is home to the world's largest telescope -- but the stargazing from here is fantastic even with the naked eye.

Setting Out -- You'll need a four-wheel-drive vehicle to climb to the peak, Observatory Hill. A standard car will get you as far as the visitor center, but check your rental agreement before you go; some agencies prohibit you from taking your car on the Saddle Road, which is narrow and rutted, and has a soft shoulder.

Safety Tips -- Always check the weather and Mauna Kea road conditions before you head out (tel. 808/961-5582). Dress warmly; the temperatures drop into the 30s (around 0°C) after dark. Drink as much liquid as possible, avoiding alcohol and coffee, in the 36 hours surrounding your trip to avoid dehydration. Don't go within 24 hours of scuba diving -- you could get the bends. The day before you go, avoid gas-producing foods, such as beans, cabbage, onions, soft drinks, or starches. If you smoke, take a break for 48 hours before to allow the carbon monoxide in your bloodstream to dissipate -- you need all the oxygen you can get. Wear dark sunglasses to avoid snow blindness, and use lots of sunscreen and lip balm. Pregnant women and anyone under 13 or with a heart condition or lung ailment are advised to stay below. Once you're at the top, don't overexert yourself; it's bad for your heart. Take it easy up here.

Access Points & Visitor Centers -- It's about an hour from Hilo or Waimea to the visitor center and another 30 to 45 minutes from here to the summit. Take the Saddle Road (Hwy. 200) from Hwy. 190; it's about 19 miles to Mauna Kea State Recreation Area, a good place to stop and stretch your legs. Go another 9 miles to the unmarked Summit Road turnoff, at mile marker 28 (about 9,300 ft.), across from the Hunter's Check-in Station. People usually start getting lightheaded after the 9,600-foot marker (about 6 1/4 miles up the Summit Rd.), the site of the last comfort zone and the Onizuka Visitor Information Station (; tel. 808/961-2180). Named in memory of Hawaii's fallen astronaut, a native of the Big Island and a victim of the 1986 Challenger explosion, the center is open daily from 9am to 10pm.

Everything You've Always Wanted to Know About Mauna Kea -- One of the best books on Mauna Kea, written by Onizuka Visitor Information Station manager David Byrne and Big Island writer Leslie Lang, is Mauna Kea: A Guide to Hawaii's Sacred Mountain (Watermark Publishing). The book covers everything from the cultural history of the sacred mountain to her natural history, even great insights on the scientific value of the dormant volcano. Plus, the authors give valuable tips on how to make the most of your visit to truly one of the wonders of the world.

Tours & Programs -- If you'd rather not go it alone to the top, you can caravan up as part of a free summit tour, offered Saturday and Sunday at 1pm from the visitor center (returns at 5pm). You must be 16 or older and in good health (no cardiopulmonary problems), not be pregnant, and have a four-wheel-drive vehicle. The tours explain the development of the facilities on Mauna Kea and include a walking tour of an observatory at 13,796 feet. Call tel. 808/961-2180 if you'd like to participate (

Every night from 6 to 10pm, you can do some serious stargazing from the Onizuka Visitor Information Station. There's a free lecture at 6pm, followed by a video, a question-and-answer session, and your chance to peer through 11-, 14-, and 16-inch telescopes. Bring a snack and, if you've got them, your own telescope or binoculars, along with a flashlight with a red filter. Dress for 30° to 40°F (-1° to 4°C) temperatures, but call tel. 808/961-5582 for the weather report first. Families are welcome.

At the Keck Telescope Control Center, 65-1120 Mamalahoa Hwy. (Hwy. 19), across from the North Hawaii Community Hospital, Waimea (; tel. 808/885-7887), you can see a model of the world's largest telescope, which sits atop Mauna Kea. The center is open Monday through Friday from 8am to 5pm. A 12-minute video explains the Keck's search for objects in deep space. From10am-2pm the center is staffed with volunteers to help educate visitors.

The W. M. Keck Observatory at the summit does not offer tours, but it does provide a visitor gallery with a 12-minute video, informational panels on the observatory layout and science results, two public restrooms, and a viewing area with partial views of the Keck telescope and dome. Gallery hours are Monday through Friday from 10am to 4pm.

Making the Climb -- If you're heading up on your own, stop at the visitor center for about a half-hour to get acquainted with the altitude. Walk around, eat a banana, and drink some water before you press onward and upward in low gear, engine whining. It takes about 30 to 45 minutes to get to the top from here. The trip is a mere 6 miles, but you climb from 9,000 to nearly 14,000 feet.

At the Summit -- Up here, 11 nations, including Japan, France, and Canada, have set up peerless infrared telescopes to look into deep space. Among them sits the Keck Telescope, the world's largest. Developed by the University of California and the California Institute of Technology, it's eight stories high, weighs 150 tons, and has a 33-foot-diameter mirror made of 36 perfectly attuned hexagon mirrors, like a fly's eye, rather than one conventional lens.

Also at the summit, up a narrow footpath, is a cairn of rocks; from it, you can see across the Pacific Ocean in a 360-degree view that's beyond words and pictures. When it's socked in, you get a surreal look at the summits of Mauna Loa and Maui's Haleakala poking through the puffy white cumulus clouds beneath your feet.

Inside a cinder cone just below the summit is Lake Waiau, the only glacial lake in the mid-Pacific and, at 13,020 feet above sea level, one of the highest lakes in the world. The lake never dries up, even though it gets only 15 inches of rain a year and sits in porous lava where there are no springs. Nobody quite knows what to make of this, but scientists suspect the lake is replenished by snowmelt and permafrost from submerged lava tubes. You can't see the lake from Summit Road; you must take a brief high-altitude hike. But it's easy: On the final approach to the summit area, upon regaining the blacktop road, go about 600 feet to the major switchback and make a hard right turn. Park on the shoulder of the road (which is at 13,200 ft.). No sign points the way, but there's an obvious .5-mile trail that goes down to the lake about 200 feet across the lava. Follow the base of the big cinder cone on your left; you should have the summit of Mauna Loa in view directly ahead as you walk.

Experiencing Where the Gods Live

"The ancient Hawaiians thought of the top of Mauna Kea as heaven, or at least where the gods and goddesses lived," according to Monte "Pat" Wright, owner and chief guide of Mauna Kea Summit Adventures. Wright, the first guide to take people up to the top of Mauna Kea, the world's tallest mountain when measured from the base and an astonishing 13,796 feet when measured from sea level, says he fell in love with this often-snowcapped peak the first time he saw it.

Mauna Kea Summit Adventures offers a luxurious trip to the top of the world. The 7- to 8-hour adventure begins midafternoon, when guests are picked up along the Kona-Kohala coasts in a custom four-wheel-drive turbo-diesel van. As the passengers make the drive up the mountain, the extensively trained guide discusses the geography, geology, natural history, and Hawaiian culture along the way.

The first stop is at the Onizuka Visitor Information Station, at 9,000 feet, where guests can stretch, get acclimatized to the altitude, and eat dinner. As they gear up with Mauna Kea Summit Adventures' heavy arctic-style hooded parkas and gloves (the average temperature on the mountain is 30°F/-1°C), the guide describes why the world's largest telescopes are located on Mauna Kea and also tells stories about the lifestyle of astronomers who live for a clear night sky.

After a dinner of ribs, chicken, and jasmine rice served hot or tofu/spinach wrap (cold), and a brownie, everyone climbs back into the van for the half-hour ride to the summit. As the sun sinks into the Pacific nearly 14,000 feet below, the guide points out the various world-renowned telescopes as they rotate into position for the night viewing.

After the last trace of sunset colors has disappeared from the sky, the tour again descends down to midmountain, where the climate is more agreeable, for stargazing. Each tour has Celestron Celestar 1100 deluxe telescopes, which are capable of 30* to 175* magnification and gather up to 500 times more light than the unaided eye.

Wright advises people to book the adventure early in their vacation. "Although we do cancel about 25 trips a year due to weather, we want to be able to accommodate everyone," he says. If guests book at the beginning of their vacation and the trip is canceled due to weather, then Mauna Kea Summit Adventures will attempt to reschedule another day.

Note that the summit's low oxygen level (40% less oxygen than at sea level) and the diminished air pressure (also 40% less air pressure than at sea level) can be a serious problem for people with heart or lung problems or for scuba divers who have been diving in the previous 24 hours. Pregnant women, children under 13, and obese people should not travel to the summit due to the decreased oxygen. Because the roads to the summit are bumpy, anyone with a bad back might want to opt out, too.

The cost for this celestial adventure is $200 including tax (15% off if you book online 2 weeks in advance). For more information, go to or call tel. 888/322-2366 or 808/322-2366.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.