Procedures and Guidelines for Subaru Telescope
summit facility Tours

We are honored by your interest in visiting the Subaru Telescope summit facilities. We are glad to be able to offer the public an opportunity to see the technology and setting which makes Subaru Telescope one of the leading observatories in the world.

To make the tour safe and enjoyable, we ask all visitors and potential visitors to become familiar with our procedures and guidelines before signing up for a tour and before coming to Maunakea.

The high altitude of Maunakea poses a significant health hazard to all visitors. In particular, the relative lack of oxygen at high altitudes affects our ability to make accurate judgment. Learning the effects of high altitude and taking precautions will help make your visit safe and enjoyable.

The tour begins and ends in the Subaru Telescope enclosure. The telescope enclosure is not a building designed for human occupation, but an integral part of a large precision scientific instrument. Our guide will lead visitors along the safest and shortest route to a good view of the telescope. However, there are no restrooms or sitting areas along the route.

In this document we have outlined the requirements and procedures of the Subaru Telescope facility tours and guidelines that will help visitors have a safe and comfortable tour.

  1. Requirements for Participation
  2. Tour Day Procedures
  3. Guidelines for Safety and Comfort
  4. Driving Safely to Maunakea
  5. Other Guidelines


1. Requirements for Participation

  • For safety reasons, people under the age of 16, people who are pregnant, and people who have physical conditions that recommended against travel to high altitude may not participate in the tour. We recommend that you consult a medical professional if you have any concerns about the effect of high altitude on your health.
  • Only visitors with a confirmed prior reservation who have submitted liability waiver forms can participate in a tour. We will not accept anybody who shows up on the day of a tour. Please do not bring anybody along with you who does not have a reservation.
  • Once the tour begins, instructions of our summit guide must be followed without delay at all times. Our summit guide's main job is to safeguard both visitors and the telescope. Our summit guide is familiar with the effects of high altitude and how to respond to them.
  • Do not enter any area that is not part of the designated tour route. There are delicate scientific instruments and safety hazards throughout the enclosure. An accident can jeopardize your health, our research, or both.
  • Please understand that there may be circumstances under which we may be forced to cancel a tour at the last moment. Weather occasionally prohibits access to the Maunakea summit area. An emergency situation, where the continuation of a tour threatens the safety of visitors or the operation of the telescope, may force us to discontinue a tour at the last moment or mid-tour.
  • Please arrive at the meeting point on time. If you suspect that you may be late please contact us as soon as possible at 808-895-7390. If you are delayed for over 15 minutes without notice, your reservation will be cancelled. Even if we receive warning, we may be forced to cancel your reservation if your delay affects our ability to give the next scheduled tour or interferes with telescope operations.
  • Make sure you have sufficient health insurance to cover the medical cost that you may incur due to an injury or illness at the summit.


2. Tour Day Procedures

  • Make sure you know how to get to Maunakea. The University of Hawaii Institute for Astronomy has published maps of the Big Island and of the Maunakea summit area on their web page (
  • Leave for Maunakea in time to check in a the Onizuka Center for International Astronomy Visitor Information Station (VIS) one and a half hours before the tour. From Kona this would be about 3.5 hours before the tour, from Hilo this would be about 2.5 hours before the tour.
  • At the 9200 ft (2800 m) level, you will find the VIS. Spend an hour at the VIS to allow your body to adjust to high altitude. The longer you stay at VIS the more comfortable you will be once you arrive at the summit area.
  • Drive to summit area to be at gathering spot 5 minutes before the tour. From the VIS to the Subaru Telescope enclosure generally takes 45 minutes.
  • Park in the Visitor Parking Area and wait for our summit guide to open door.
  • Sign-In at beginning of tour. All visitors must wear hard hats that Subaru Telescope will provide while in the telescope enclosure.
  • Enjoy the 45 minute tour.
  • If you are delayed more than 15 minutes or have some trouble, please notify Subaru Telescope by calling or leaving a message with +1-808-895-7390.


3. Guidelines for Safety and Comfort

The summit of Maunakea is at 13796 ft (4205 m). The air pressure in the summit region is less than 60% of that at sea level, and the body must work harder to obtain oxygen. Altitude sickness is a risk for all visitors. All visitors should expect a reduction in both their physical and mental capabilities. The stress caused by the high altitude environment can also worsen any existing health problems.

To maximize your comfort at altitude and minimize the risk of altitude sickness, please follow the following guidelines:

  • Refrain from smoking and alcohol for the 24 hours before your visit to Maunakea and during your visit. Smoking and the consumption of alcoholic beverages are prohibited within the Subaru Telescope summit facilities.
  • Avoid gas producing foods (such as beans, cabbage, onions, for example) on the day before your visit. Gas expands when air pressure decreases, and this is true for gas inside the human body.
  • Bring warm clothing. The inside of the enclosure is chilled to the expected night time temperature of the summit which is typically around 32°F (0°C). The summit is cold even during the day when the weather is cloudy or windy. You may wish to bring gloves so your hands don't get chilled from touching cold metal railings.
  • Wearing sturdy closed toe shoes is a mandatory requirement for the tour. The enclosure is cold, and the walking surfaces along the tour route include concrete floors and metal gratings. In case of an emergency, evacuation of the enclosure involves steep ladders.
  • Stay hydrated. Dehydration can make you more susceptible to altitude sickness.
  • Stay hydrated. The humidity in the summit area is typically only 10%. You may want to bring lip balm and hand lotion.
  • Go to the rest room whenever you have the opportunity. One of the effects of altitudes is increased frequency of urination. There are no restrooms along the tour route.
  • Protect yourself from UV radiation. Less atmosphere, more harmful UV radiation. If you intend to spend much time outside in the Maunakea summit area, wear sun block and sun glasses.
  • Move at half your usual speed. Make a conscious effort to avoid sudden movements. For example, if you drop something, avoid jerking your head to see where it falls and take your time picking it up.
  • Remember to breath. While on the summit, try to breath consciously, using slow deep breaths.
  • Talk to people and keep others informed of how you are feeling. It is hard not to breath if you talk.
  • Tell our summit guide immediately if you begin to feel ill.
  • Don't take chances. If you are not feeling well on the day of your tour, we recommend that you do not participate in the tour. The altitude is likely to worsen your condition, and chances are you will not enjoy the tour. If you require medical attention once you are at the Maunakea summit area, the closest medical facilities will be over 1.5 hours away by car.
  • Person with claustrophobia may not feel comfortable when using an elevator to access the telescope floor.


4. Guidelines for Driving to the Maunakea Summit Area

  • The summit of Maunakea is only accessible by a four wheel drive vehicle. The information is available at this page.
  • The driving time to the Subaru Telescope summit facility is about 2.5 hours from Hilo and 3.5 hours from Kona, including a one hour stop to acclimatize to high altitude at the VIS. Traffic and bad weather increase these driving times.
  • The Saddle Road (Highway 200) that links the Kona and Hilo areas to Maunakea is often foggy. Turn on your headlights to increase your visibility to other cars.
  • The speed limit above the VIS is 25 mph (40 km/h). The slope is steep, so shift to a low gear when descending. Relying on your breaks alone could lead to break failure. It takes about 30 minutes between the VIS and the Subaru Telescope summit facility.
  • The speed limit on the dirt road leading to the Subaru Telescope summit facilities is 5 mph (8 km/h) to prevent dust from settling on the antennas of the Sub-Millimeter Array.
  • A grader levels the unpaved road several times a week. Make sure that the driver of the grader is aware of your presence before you try to pass.
  • Park in the designated parking area once you reach the Subaru Telescope summit facility. Do not walk or drive on the cinder.


5. Other Guidelines

  • The telescope enclosure, in particular the upper portions, are an integral part of the telescope. As such, it does not have facilities that you may expect in a regular building and does not conform to regular building codes and is not ADA compliant. Please let us know in advance if there you need special assistance.
  • Visitors must wear hard hats at all times while in the Subaru Telescope enclosure.
  • The tours will be in Japanese or English.
  • There are no restrooms along the tour route. Please make sure to use the restrooms at the VIS before you depart for the summit. If you need to use a rest room once you arrive at the summit, please use the portable toilets located at the Y intersection near the Caltech Sub-millimeter Observatory, the portable toilets near the United Kingdom Infrared Telescope, or the public restrooms at the W. M. Keck Observatory's visitor gallery.
  • Feel free to take photos or videos along the tour. However, do not stray from the tour route or fall behind the tour.
  • Please refrain from eating during the tour. You may bring along a water bottle or other beverage to keep your self hydrated during the tour.
  • Do not litter any where in the summit area of Maunakea, indoors or out.
  • Remember that one of the effects of altitude is forgetfulness. Try not to misplace any of your belongings.
  • Bring only necessary items with you along the tour. Carrying heavy bags will hasten your fatigue and exacerbate any discomfort.
  • While outside of the Subaru Telescope enclosure, stay on paved surfaces. The cinder areas are fragile.


Symptoms of High Altitude Sickness


Some degree of breathlessness and drowsiness is normal at high altitude. Headaches are common, but are a sign that you should descend to lower altitude. Descend to lower altitudes is an integral part of any response to high altitude sickness.

Here are some of the symptoms of severe altitude sickness that require immediate descent to lower altitudes. Please note that this list is not complete, and the descriptions do no not necessarily conform to standard medical terminology. The list is meant to illustrate some of the serious consequences of high altitude sickness and some symptoms that may appear innocuous but indicate serious illness.

Problems of the Central Nervous System:
Confusion, drowsiness, incoherent speech, acute headaches, anxiety.
Problems of the Respiratory System:
Shortness of breath, shallowness of breath during conversation, breathing difficulties. Shortness of breath while resting. Hyperventilation (over 40 breaths a minute). Coughing up foam. Bloody phlegm.

Problems of the Circulatory System:
An increase or decrease in heart rate. Chest pains. Cardiac arrest.
Other accompanying symptoms:
Lack of coordination. Loss of balance. Stumbling. Problems with hearing and seeing, in particular the loss of peripheral vision. Loss of sensation in extremities. Aches in the stomach region. Severe nausea. Throwing up.



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