To go to the other side of the planet to the largest telescopes in the world, work at the altitude of the Tatra peaks and "commute" to work by plane? This is exactly how Jan Foltýn, a doctoral student from the Faculty of Mechanical Engineering, worked for seven months. Thanks to his study visit, he managed to get into a team that takes care of a set of telescopes for observing the distant universe at the European Southern Observatory in Chile.

Don't be fooled by the headline, Jan Foltýn is no astronomer. As part of his PhD at the Institute of Machine Design, he focuses on hydrostatic bearings, which seem to be quite distant from the universe. However, it is on them that telescopes rotate, including the largest in the world, which you would find at the Paranal Observatory in a remote part of the Atacama Desert. The so-called Very Large Telescope consists of four telescopes with deposits with a diameter of twenty meters. Nearby is the world's largest telescope, the Extremely Large Telescope (ELT).

You got to Chile thanks to a study stay at ESO ( European Southern Observatory). What was your task?

My job work focused on the four telescopes that make up the VLT, especially their hydrostatic mounting. I joined the team in charge of technical support for the telescope operation. And I was also assigned to three development projects in the field of hydrostatics.

So should I imagine your normal day as putting on overalls and going to repair the telescope?

Actually, yes (laughs). We took our helmets, and overalls and went to the telescope. Everyone else worked on the upper surface, while our team went "to the basement", where there is a twenty-meter ring of the bearing and where we carried out maintenance or solved problems. During the day, engineers need to maintain the telescope so that astronomers can make their observations at night. If something fails to be resolved during the day, it's a waste of precious viewing time that is being fought hard for. Everyone has a clearly defined time when they can make their observations, and the conditions also prioritize it: if the conditions are good, groundbreaking observations take precedence.

In the Atacama Desert, which is far from light smog, there was probably not such a problem with the conditions, was it?

The weather here is stable. Although I was lucky enough to experience rain in the desert, even though it is the driest place in the world where it rains once every five years. We even had to carry out the procedure of covering the telescope against rain, which was interesting.

As far as the weather is concerned, the problem is mainly with the moon – at the time of the full moon, the conditions for observation are worse. Otherwise, it's a very good area. When you look at the night sky even with your eyes, it seems unreal. Even the Milky Way was beautifully visible...

We're talking about the largest telescopes in the world, at least until the ELT was built. What types of problems did you have to deal with and what causes them?

Quite often, the causes of issues were related to temperature and humidity. Although the observatory is located in the desert, there are large fluctuations in temperature, especially between day and night. The bearing suffers from temperature changes, especially the viscosity of the oil. Quite often, the thickness of the lubricating film dropped, which in turn created problems in other systems of the telescope. Just to give you an idea, we are talking about changes in the thickness of the lubricating film in the order of micrometres.

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I also went to see Cerro Armazones, where the world's largest telescope ELT is being built. It is an incredible building, its bearing will have a diameter of fifty meters.

You also "commuted to work" in an interesting way during your stay, didn't you?

The working time was divided into eight days at the observatory and six days in Santiago, where my "home" was. This rhythm was important to relax. It may not seem like it, but Paranal is a rather stressful environment for the human body: it's a desert, you're in a really remote place, and high up on top of that... On the first day of my shift, I flew some 1,000 kilometres from Santiago to Antofagasta, where an ESO bus picked us up and drove another 200 kilometres to the observatory. There we had accommodation, food, just everything arranged for the time of the shift. In total, there were an estimated eighty people on the shift: from astronomers and technicians to support activities in the form of cleaning, catering or production of parts for the telescope.

You mentioned it before, Paranal lies at a relatively high altitude. How did you cope with it?

In the beginning, it was a bit of a shock for the body. When I was introducing myself with a short presentation at the beginning of my stay, I started at my normal pace and suddenly I was out of breath while speaking, I had to slow down.

The hotel at the observatory, where we stayed during the shift, is 2400 meters above sea level, and the observatory is about thirty meters higher. So, it was quite noticeable: when you got up faster, you could feel it, you had to follow the drinking regime. And there is also a high intensity of sunlight, you get burned quite easily.

You also mentioned the development projects you were given. What did they embrace?

The first task was to design a methodology for replacing the telescope's hydrostatic bearing. Next, I was supposed to analyze the state of the telescopes, it was more of a computational project. And for me, the most interesting was the design of the methodology for measuring the thickness of the lubricating film of the hydrostatic bearing of the telescope.

What is the most valuable experience for you that you take home?

I was fascinated by how people can work in such a highly stressful environment in a very calm manner. There was no hurry, everything was done very precisely and thoughtfully.

As far as professional experience is concerned, it is very well transferable to us and to industrial practice. I really had the opportunity to see the largest bearings in the world and they work practically on the same principle as ours in laboratories, only they have slightly different problems and ways of operation. But it was definitely an incredible experience.

Finally, I cannot help but ask if you had the opportunity to get to know Chile itself and its culture in your free time.

I admit that I went there with the idea of speaking English, and after two days in Santiago, I found out that only a small percentage of Chileans speak English. And I spoke zero Spanish. So, the beginnings were really hard, I survived on five basic phrases, but gradually my Spanish improved.

And of course, I also went on trips around the area, the mountains around Santiago were unbelievable. Later I managed to see the desert, specifically San Pedro, which is the gateway to the Atacama. And I also managed to travel the very south to Patagonia, to the glaciers there. Nature in Chile is truly untouched and extremely diverse.