week with the stars
Barbara Burtscher, a 20-year-old Swiss student of physics at
Zurich University, won the Special Donated Prize at the 16th European
Young Scientists Contest in 2004 for her work on the 153P/Ikeya-Zhang comet. Her
reward was a trip to the European Southern Observatory in Paranal, Chile. Read
7 March 2005,
Zurich airport. I still couldn’t really believe it. Here I was, about to fly to
Chile to discover the famous giant telescopes at the European Southern
Barbara on the road to the stars.|
Over the past four years I had spent many long nights
gazing at the stars in the Swiss sky, dreaming of better weather conditions and
larger expanses free of light pollution. Chile is an ideal country for
astronomers, with its cloudless skies, large areas unpolluted by light, and
mountains whose summits rise up high into the earth’s atmosphere. All good
reasons why the Andes were chosen as the site for the large European
observatories. From the plane I suddenly caught a glimpse of their cloud-shrouded
summits rising up sharply from the plain, a mountain range that still presents
an obstacle to man and animals. The longest mountain range in the world.
I was met at the airport by a member of the ESA staff who drove me to the guest
residence in Santiago – a single-storey building with an ornamental pond in the
interior courtyard and set in a garden. A haven of peace where I was really
It was there that I met Valentina Rodriguez, who had organised
my visit to the observatory. It was she who drove me around, visiting all the
installations and sites where the astronomers worked. I then went off to
discover a little of Santiago, a city of 6 million inhabitants. Everything was
new to me, from the beggars squatting in the streets to the incredible tangle of
the power lines…
2. The VLT
next day I was off to Antofagasta, 1 200 km to the north. Then on again, with a
group of astronomers, along the rather bumpy roads to a platform sited high in
the Cerro Paranal, at 2 635 metres in altitude, deep in the Atacama Desert – the
site of the Very Large Telescope (VLT).
Flying over the Andes.|
© Barbara Burtscher
The installation consists of
four main telescopes – 'Antu', 'Kueyen', 'Melipal' and 'Yebup' – with a main
lens of 8.2 m in diameter, and four auxiliary 1.8 m telescopes. This largest and
most modern optical interferometric installation in the world has already
enabled some spectacular scientific progress.
For two days I stayed at La
Residencia, the accommodation for site staff and visitors. It is an
underground building topped, at ground level, with a dome housing a swimming
pool and miniature artificial jungle.
The astronomer Emmanuel Jehin took
me to visit the VLT. After donning my protective helmet in the control room we
passed along the passages hewn into the rock until we reached the main
telescope. I visited the interior. It was really impressive! It was so big that
it was impossible to photograph it all in a single frame.
3. A southern night
Astronomical observations are carried out at night and any artificial light is
strictly forbidden. Cars drive on the mountain roads of the Cerro Paranal using
sidelights only, guided by luminescent diodes found at the side and in the
middle of the roads, like aircraft on a runway. In the total darkness, this is
an incredible experience.
Flames, ready to observe 150 stars at a time…|
© Barbara Burtscher
The night I was there was marvellously bright,
nothing like the kind of sky I am used to. At first I was able to recognise
hardly any of the stars, but finally I picked out the Southern Cross and Orion,
with its head facing downwards.
During the day I had watched the
telescope operators as they drew up their checklists. I had also been shown
Flames, a device that enables you to observe 150 stars all at the same time and
to make spectral analyses. I was excited at the prospect of being able to watch
the astronomers at work during the night in the control room and the chance to
ask them all my questions. However, after a few hours I was simply too tired to
4. Star Track
The next day I followed the
route known as Star Track to the VLT where I was treated to a guided tour of the
interferometric installations (VLTI). The VLTI, with its four giant telescopes,
together with four other smaller telescopes located on the platform,
concentrates the light that enters the atmosphere in an underground tunnel. This
produces an optical resolution of as much as 0.005 arc seconds, enough to pick
out an astronaut on the Moon!
Sunset over La Silla, seen from the control room. On the right, the NTT
During the day, the weather conditions
steadily worsened. The air humidity soon reached a critical level beyond which
condensation could pose a threat to the telescope optics. A single droplet on
the lens could be fatal, so they were all positioned to rule out any danger of
Clouds obscured the sky and it was clear that there would
be no observation that night. We all took the road back to the Residencia to
attend the station’s monthly party. Time just flew by.
5. La Silla in the rain
After a few hours’ sleep I took a last quick
look at the telescope platform before taking the road back to Antofagasta. Then
it was La Serena, the long road that borders the Pacific, and finally a dusty
track. We came to a sign marked La Silla and there, on a distant mountain, we
could just make out up ahead the dome of a telescope.
La Silla is the
first of the ESA’s astronomical stations as you head south, located 160 km from
La Serena at 2 400 m in altitude. It has 17 telescopes. It is here that the
technological innovations intended for the giant telescopes (such as active and
adaptive optics) are developed and tested before being used on the VLT.
It was raining and the wind was blowing. I was given a room and torch – part of
the survival equipment for astronomers working at these altitudes. Fernando
Selman then showed me around the installations which were simply incredible.
Most impressive of all the telescopes was the NTT (New Technology Telescope)
with a diameter of 3.5 m, built in 1989. The structure housing the telescopes
pivots along with the actual telescopes. Fernando organised a demonstration for
my benefit so that I could see, from the inside, the movement of the telescope
and that of the building itself.
We witnessed a magnificent sunset from
the control room, affectionately known as ‘The Ritz’ by the astronomers, but the
weather continued to deteriorate and the fog became so thick that nobody dared
venture outside. The culmination of the evening’s events was a visit to the 1.2
m Geneva telescope used to detect planets beyond our solar system. Being Swiss,
I understood why it was painted red and white.
The next morning, under a
bright blue sky, I took the road back to Santiago and enjoyed a final excellent
meal at the ESA guesthouse.
After – fortunately – finding stamps at the
airport to send off about 30 postcards, it was time for the long flight back to