Get an out-of-this-world view with a tour of the Big Island’s Subaru Telescope

The 40-minute tour will take you to see some of the world's strongest astronomical telescopes.

Are you game? If so, the 40-minute tour of the Subaru Telescope will literally whisk you out of this world. Mauna Kea, on Hawaii Island, is regarded as one of the best sites in the world for astronomical research. Thirteen observatories operated by 11 countries are clustered on its peak; the Subaru Telescope, part of the National Astronomical Observatory of Japan, is the only one offering regularly scheduled tours to the public.

Standing on a balcony that’s 40 feet high, you’ll view Subaru’s optical-infrared telescope, which is among the largest of its kind in the world. With a primary mirror that weighs 22.8 tons and measures 27 feet in diameter, it can capture images of celestial bodies up to 12.88 billion light-years away.

The cylindrical dome that houses the telescope is made of aluminum, which reflects the sun’s rays. This helps keep the interior between 32 degrees and 40 degrees Fahrenheit, which is consistent with nighttime temperatures atop Mauna Kea (blurred images can result during observations if there’s too much of a difference between the inside and outside temperatures), so dress accordingly.

It takes about four hours to drive from the Big Island’s west side to the summit of Mauna Kea, including at least 45 minutes of acclimation time at the Onizuka Center for International Astronomy’s Visitor Information Station at the 9,200-foot elevation. You’ll need to arrange your own transportation, either by renting a four-wheel-drive vehicle or hiring a driver and van from a licensed commercial tour operator. The University of Hawaii’s Institute for Astronomy notes on its website: “The high altitude of the observatory carries serious health risks and routinely impairs physical and mental activity. Children under 16; pregnant women; and people with respiratory, heart or severe overweight conditions are advised not to go higher than the Visitor Information Station. Scuba divers must wait at least 24 hours after their last dive before traveling to the summit.”

Tours of the Subaru Telescope are available by reservation only. They are not open to people who are pregnant, under the age of 16 or who have health concerns (e.g., serious heart and respiratory conditions) that make them susceptible to altitude sickness. A maximum of eight people is allowed for each tour, and reservations must be made online at least a week in advance. Go to and look for the “Visiting Subaru” link; tour schedules for each month will be posted online three months in advance.

Categories: Activities, Hawai‘i Island