Guided visit


OSN guided tour is aimed at the general public. During the visit, you will see the telescopes and instrumentation located in the main building and we will explain their operation. The OSN is a high mountain observatory and the snow makes very difficult to access the facility during most of the year. Thus, visits are carried out only on the scheduled dates of July and August, provided that weather conditions permit it. Night visits are not allowed.



Buy tickets on-line

Rules and recommendations for the visit

Number of people: for security reasons, no more than 25 people are allowed to access the OSN facilities.

Age: Minors must be accompanied by an adult at all times. For security reasons, the minimum age required for visiting the OSN is 10 years old.


  • The observatory is located at 2900 meters above sea level. At this altitude, the oxygen content of air is reduced. Therefore, the guided visit is not recommended for people suffering from heart and respiratory problems, as well as elderly people, or people with other medical conditions that may be affected for the reduced oxygen content. The OSN do not have any medical assistance in its facilities.
  • At all times during the visit you must be accompanied by the authorized guide.
  • Although the visit takes place in the summer months, it is necessary to bring warm clothes and appropriate shoes for the mountain.

Very important: The OSN may cancel the visit, even in a very short notice, due to adverse weather conditions (wind, bad weather, etc.) that may affect the safety of the visitors during the access to the observatory. Should this conditions happen, the company managing the activity will contact the visitors as soon as possible.

For more information: visitas-osn [at]