Travel to APEX/Sequitor

Please note that visitors are received by appointment only.

No public visits are offered at the APEX base in Sequitor.

The APEX Sequitor Base, located near San Pedro de Atacama in Chile, is the workplace of the astronomers and support staff running APEX, the Atacama Pathfinder Experiment, a 12-metre antenna allocated at 5100 metres altitude on the Chajnantor plateau. Sequitor Base is also an administrative point that supports the operation of the antenna and serves as connection between APEX and the rest of the ESO sites in Chile. It is also an important contact point for the local authorities and the people of the Sequitor community.

APEX is a collaboration between the Max-Planck Institute for Radioastronomy (MPIfR), the Onsala Space Observatory (OSO) and the European Southern Observatory (ESO). The telescope is operated by ESO.

How to reach APEX/Sequitor

Arriving by plane

Please note that airfares to and from Chile can get quite expensive when booking less than three months in advance. The closest airport to APEX/Sequitor is the El Loa International Airport in Calama. Public transportation is available only as far as San Pedro de Atacama.

Arriving by car

There are several car rental companies available at the airport, including Alamo, Budget, Econorent and Hertz. The average daily cost of a car in Calama rises to CLP 65 000 (about EUR 100) and it takes about two hours to drive to APEX/Sequitor from the airport. For driving directions from the airport, please check this map.

To drive from a different city, take the Pan-American Highway as far as the turn for route 25 to Calama. Pass the El Loa International Airport and take route 23 to San Pedro de Atacama. Just before San Pedro there is a road to the right to Sequitor and down the road to the right, before reaching the turn to Toconao, there is an access road to APEX/Sequitor. It takes around four hours to reach APEX/Sequitor from the Pan-American Highway.

For driving directions from another city, please see this external map.

Further references on how to reach APEX/Sequitor are available here.

Accommodation in APEX/Sequitor

It is not possible to stay overnight at APEX Sequitor. Media visits are allowed on special request. For further information on media visits please check here.

ESO staff and special visitors usually stay at dormitories in APEX/Sequitor or at La Casa de Don Tomás in San Pedro de Atacama.

Food at APEX/Sequitor

ESO staff and visitors usually eat at the facilities in APEX/Sequitor. Other than that, there is no possibility of obtaining food.

Further information on restaurants in San Pedro de Atacama is available here.

Health & Safety

Weather and Clothing

APEX/Sequitor is located on a remote site in the middle of the driest desert in the world. You may be exposed to strong winds and construction/maintenance areas. Please wear appropriate clothing such as trousers, walking shoes (no sandals), sunglasses, etc. Bear in mind that night time temperatures are cold, often below zero, so bring adequate clothing. The average humidity on Sequitor is very low.

High Altitude Health Issues

If while staying in La Silla you experience any of the following, please report it to a local staff member immediately: acute headache, dizziness, breathing problems, ringing or blocking of ears, heart pains, acute muscular pains, seeing "stars". If you are visiting the APEX — ALMA sites or any other ESO facilities in Chajnantor, please check for additional High Altitude Health Information in the Travel to Chajnantor — APEX and ALMA Operational Support Facility (OSF) page.


  • Drink extra water or juice. Do not drink water from the faucets.
  • Alcohol is forbidden at all ESO high altitude sites, not only because of its inebriating properties, but also because it can increase the risk of dehydration.
  • Eat light, high-carbohydrate meals.
  • Avoid sedatives and similar medication.
  • Never use medicinal treatment instead of descending, without consulting an ESO physician or paramedic at the site.
  • Use skin protection: wear a hat and clothing that covers arms and legs; apply a broad-spectrum sunscreen of sun protection factor 15+ liberally on areas of the body not protected by clothing, and reapply it frequently.
  • Use eye protection: wear UV-protection sunglasses of a wrap-around design, and a wide-brimmed sun hat.

View APEX/Sequitor in a larger map

APEX Sequitor Base
Ayllo de Sequitor, Parcela 85
San Pedro de Atacama
II Region