The total mirror surface is 240 m2, corresponding to a reflector diameter of 17 meters. The telescope's camera consists of a densely packed matrix of photomultipliers that register the Cherenkov light. It is read out by extremely fast electronics. Exposure times of one hundred millionth of a second are necessary for the images of the air showers. By analyzing the shape and orientation of the shower images, the aerial images of the cosmic gamma quanta can be efficiently distinguished from the background. The energy of the gamma is estimated from the total brightness of the air shower. The trigger energy threshold of the Magic | telescope is approx. 50 GeV.
MAGIC Il rights (2009)
Another Cherenkov telescope was erected 85 meters away from the MAGIC telescope. It is identical to MAGIC I except for the aluminum reflectors. These have a side length of one meter and therefore four times the surface area. The aim of this extension is to improve the low photon yield of low-energy showers. By observing air showers in parallel with both telescopes, the detection limit of Cherenkov flashes is improved by a factor of 3, which means that weaker gamma sources can also be detected.
Today, astrophysicists conduct research with huge telescopes, some of which are interconnected across continents. MAGIC is the name of the two large Cherenkov telescopes at the Roque de los Muchachos Observatory on the Canary Island of La Palma. They detect cosmic gamma rays produced by extreme processes in the universe. MAGIC I and II can be focused on any point in the firmament in just a few seconds. Mosaic-like mirror plates align themselves with a pre-aligned laser point. They are each driven by two high-precision, dynamic Carry 12 x 2 mm ball screw drives from Eichenberger.
The cosmos captivates us
In contrast to many other fields of research, astronomy is fascinating in a very special way. It seems to appeal to a basic need in us humans, the desire to understand our role in the universe, to find out what exists "out there in space". We take it for granted that astronomers know about the Big Bang and can explain to us how the universe has evolved in the 13.8 billion years since its birth.
In fact, we still know almost nothing about the universe. The MAGIC telescopes, which are positioned 2400 m above sea level on a volcanic slope just below the edge of the crater, are used to observe astronomical objects in space as well as to investigate questions of fundamental physics. Dark matter makes up the majority of matter. What the rest is, is still unknown. However, in order to get an overall physical picture of how our cosmos came into being, dark matter must first be understood.
Hunters of the blue light
The high-energy gamma radiation comes from the universe at the speed of light and is invisible. At an altitude of around eight kilometers, the gamma photons collide with the Earth's atmosphere and begin to interact with the molecules in the air. Fortunately for us, because gamma rays are high-energy and would kill people. However, this results in harmless particle showers - and it is precisely these that the MAGIC telescopes capture. Because the incoming particles are very fast, they produce blue flashes. This is also known as Cherenkov light. The gamma-ray flashes are invisible to the human eye, which is why the cameras in every MAGIC telescope detect the flashes reflected by the mirrors.
Targeting gamma-ray bursts from Earth is a difficult task. They can light up anywhere in the sky at any time and quickly disappear again. In MAGIC I and MAGIC II, almost a thousand mirrors focus on the most distant activities in the universe within just 20 seconds. The fact that the telescopes can focus so quickly on the source of the gamma-ray burst is thanks to their powerful drives and relatively low weight. 947 aluminum mirror segments mounted on carrier plates provide 247 m² of mirror surface. Each of the almost one thousand 50 x 50 cm mirror plates is driven on two sides by an amazingly fast and durable Carry 12 x 2 mm ball screw drive. The robust, cold-rolled screw drives align the individual mirrors to a pre-adjusted laser point with enormous precision and astonishing speed.
is still a mystery to science.
Working in the control center
Around 150 scientists from 24 institutions in nine European countries belong to the MAGIC collaboration. It is difficult to get observation time at MAGIC, because with 150 astro-researchers the demand is always greater than the time on offer. Using programs and computer simulations, MAGIC staff can reconstruct which particles have come down, which are uninteresting and which can ultimately provide information about the energy and where they came from in space.
It sounds as if the gamma ray detectives in the control center are sitting comfortably in front of the screen sipping coffee. But not at all! Their work is strenuous and challenging, because the technology has to function 100 percent at all times. At MAGIC, the scientists emphasize that they have the best technology in the world. Nevertheless, they still have to manually rectify failures in the computer hardware or the telescopes. In the latter case, the astrophysicists put on helmets and safety equipment and search for the fault on site. This means that they climb into the huge scaffolding of the telescopes and prove that they have a head for heights in all weathers. For example, they replace cameras or mirrors. Damage is often caused by the rough weather on the Roque de los Muchachos.
The scientists mainly work at night. On average, 4 MAGIC employees share the tasks. There is great competition for jobs in astrophysics and especially on La Palma. Research with the Cherenkov telescopes offers unique opportunities to collect and analyze data. Every theory must be verified by data. This is physics, the science of measuring, counting and understanding.
Ball screws for maximum reliability
The MAGIC constructions, each with a diameter of 17 meters, are the largest telescope mirrors of their kind in the world and also the most dynamic. To ensure that almost two thousand square mirror plates across the entire system can achieve the required short reaction time and exceptional precision, almost 4000 Swiss ball screw drives guarantee enormous power (efficiency > 0.9) with maximum functional reliability and robustness. The electrically activated Carry ballscrews convert the rotary motion of the motors into a perfect linear motion. Despite the most adverse weather conditions and large temperature differences, they fulfill their task with absolute reliability.
The Carry power profiles are manufactured and hardened cost-effectively at Eichenberger using the thread rolling process and in large series. Development, production and quality management interlock perfectly at Eichenberger. As a result, the most unusual solutions can be realized flexibly.
Always in focus: Efficient, economical overall solution for customers
Drive technology finds itself in a field of tension. Increasing time and cost pressures are set against objectives such as precise processes, high load ratings and speeds or long service life. Over the decades, an impressive range of ball and lead screw drives has been developed. Eichenberger's developers always try to build on an existing product and adapt the screw drive to the application-specific requirements. This results in a decisive price advantage and makes the customer's product more competitive.
