Laboratoire d'Annecy de Physique des Particules
Science

A « day » with an operator in La Palma

This fall, Enrique Garcia, Data-Scientist for the HESS/CTA group at LAPP, went on a 3-week shift to La Palma. Before the end of his mission, he told us about his days working on the CTA telescopes.

In La Palma, the days are quite original, because we observe all night long, and instructive because we pilot an extraordinary telescope like the LST (Large-Sized Telescope). The day starts waking up at 15h-17h. Then, at about 19h-19h30, we begin to start the telescope: we climb on the tower supporting the camera to take of the shutter. Right now, the shutter is closed because of a storm in February. So we have to take off and place back the cover by hand (picture 1).

 

Photo 1 - The telescope’s camera

Once all the checks have been made (turn on the computer, the subsystems, unlock the telescope…), we can take the LST out (photo 2) and the observation can start. The camera’s cooling system is not working properly, so we couldn’t get a lot of data. But we still made some necessary tests. Some of these tests are the alignment of the mirrors and the Bending model tests ( how the telescope is distorted depending on where it is pointing at).

Photo 2 - The LST is out

Afterwards, everything else happens in the Commissioning Container, where we control the telescope and all the systems (Drive, mirrors, camera, calibration box, lasers…). And yes, we really need all the screens you see (Photo 3).

During a normal evening, we assist the different people who need the telescope and we help them to observe or make tests. We turn on subsystems, we point the telescope, we check that everything is going well… In case there is a real problem that we can’t solve, we call the experts, and too bad if it’s 4am!

Photo 3 - The Commissioning Container

It is now 6.45-7am (after a few breaks, coffee and a sandwich at 5 am) and we start to tidy everything, turn off the systems, put away the telescope, and wait until there is enough light to go up to the tower and put the camera cover. 8-9am, it is finally time to sleep, that’s the reason why we wake up so late.

In addition to this routine, there are a few days that are different. During the first days on site, Security tours are organized to learn where all the systems are, how to use them, the problems that exist, and what to do in case of a problem. We also learn the procedures that we will use every day to start and put away the telescope. Once a week, we also have to do a visual check of the site to make sure there are no debris, or that some parts are not loose or have fallen off.

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