A smiling story of control rooms (astronomer’s folklore)…

When the control room rotates…

Some years ago, I had the privilege to be an ESO Fellow in the La Silla observatory, in Chile. I was a support astronomer, whose job was divided in half between standard fundamental research, and observatory support. I was assigned to the support (with another colleague of mine) of EMMI, the ESO-Multi-Mode Instrument (which has been used in very interesting observations, such as those of Mercury!)

EMMI was installed in one of the two Nasmyth foci of the New Technology Telescope (NTT). You may have seen his very famous and recognizable dome already.

The NTT to the left, the 3.6m telescope to the right (large white dome) with its auxiliary dome. Note how the 3.6 slit is opened by sliding “back”, but how the overall dome remains pretty “closed”. Credit: Y. Beletsky (LCO)/ESO.

From the above image, you can see how the NTT dome slit is being opened sideways. This was made to optimise the air flow through the slit and thus inside the dome. This airflow is very important to reduce the local turbulence due to the temperature difference between inside and outside the dome. This turbulence blurs the images, and quickly degrade the seeing (that’s one of those peculiar quantity used by astronomers – the subject of another post), that is, the image quality.

It is obvious in the picture above that the NTT has an extremely compact dome. What is not necessarily obvious in the NTT pictures is that its control room is rotating with the building! In fact, when pointing the telescope to a given direction, the whole building is moving, because the whole building is participating to the alignement of the telescope. The control room is located in one of the two sides of the dome. And when you are inside it, you feel exactly what you can imagine: locked inside a plastic box!

Now, let’s imagine you are in the end of a winter night, tired. Those “3rd quarter” hours when you don’t want to drink more coffee, you don’t want to smoke pipe anymore, and have read the whole internet twice already. You are just good enough for driving the next observations. You actually wait for your brain to recover a bit, as it always does when the morning light is approaching…

Suddenly, you feel you need to go relieve yourself. Big deal! Which of the two opposite exit doors of that rotating building gives you the quickest access to the toilets downstairs?!

Of course, we are scientists, and a bit engineers. Hence, there was a little utility software in the control room that was reading the azimuth value of the telescope, and telling which door was the best suited…

The Remote Integrated Telescope Zentrum…

Later in 2004, for some cost and rationality reasons, ESO decided to consolidate the control rooms of the three largest telescopes of La Silla (the NTT, the 2.2m and the 3.6m) into a single building. It has been built at the bottom of the NTT ramp:

The RITZ – the Control Room of the La Silla telescopes – is seen in front of the New Technology Telescope. On the right is the 1.2-m Leonhard Euler Swiss telescope. Credit:ESO/H.H.Heyer

It has been named the RITZ, and it was pretty comfy.

On the back of the building, there was a door with a balcony. Below is a personal picture taken at the corner of the building towards that door. We can see the SEST in the background.

Sunset is approaching…

The balcony could be walked all along the back of the building, and then to the side, providing an alternative entry/exit path to the regular door on the other side. Below is a picture of the side of the RITZ taken from that same corner.

The side of the RITZ, with the Swiss telescope dome behind the cars and the NTT ramp.

You see that small dome in the background? That’s the Swiss telescope “Euler” built and operated by my home observatory – the Geneva Observatory, home of the discoverers of the first exoplanet 51 Peg b, and Nobel Prizes in 2019 (Michel Mayor & Didier Queloz). But that’s another story.

Back to the Swiss telescope. Despite being quite strict on how to clean rooms and organise tools (the Swiss telescope is a model of rigor and smooth operations), the Swiss astronomers are very friendly. Of course, I knew many of them since I made part of my graduate studies there. And I was regularly invited “at the Swiss” to have a drink over there.

One night, I was even invited to a Swiss cheese fondue (the guys managed to bring Swiss cheese through chilean customs)! That was one of those special event you don’t want to miss when living up there in the observatory (even if the food at La Silla was probably the best of every observatory I visited – along with that of SAAO in South Africa).

I remember that night my pager making suddenly some noise (as a support astronomer, I was “on call”). I was enjoying the Swiss cheese fondue, but work was calling. Hence, I crossed the road, walked in the balcony, and entered the RITZ though the back entry. I couldn’t remember what I did exactly, but it was quick. Rapidly, I concluded and went out back to the beautiful starry night by the balcony again, light up only by the Moon.

But the white wine of the fondue was probably making some effect already. I was walking fast, and I “turned right” to walk on the building side path a bit too early… Just a bit before the end of the balcony. If by any chance you go to La Silla, and visit the RITZ, you may have a look at the balcony. Close to the corner, on the back side, the corrugated sheet of metal of the building has a little bump on it, at an height of roughly 1.7m. That was my nose…

I came back to the Swiss with some blood in the face. But everything’s was fine! And I could enjoy the end of the fondue… and the rest of the night!

The control screens of the NTT. How many hours I spent there observing the sky…

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