A close look at the stars

 

Astronomers and astrophysicists researching outer space depend on high-performance telescopes. Even here, Schaeffler’s expertise and technology have an important part to play. Schaeffler helped to equip one of the world’s largest reflecting telescopes, located on La Palma in the Canary Islands, with a rotating direct drive motor – thus helping scientists to precisely observe galaxies far away.

Perfect conditions for stargazers

When looking to the stars and exploring planets, black holes, and other distant celestial bodies, the first thing to do is find a high vantage point. Nowhere else in Europe is the night sky as dark and clear as it is when viewed from the Roque de los Muchachos ridge on La Palma (Canary Islands), which rises to a height of almost 2,500 meters and offers professional stargazers ideal research conditions thanks to the Atlantic island’s extremely low levels of light pollution.

  On the Roque de los Muchachos, astronomers can expect several large telescopes and an almost perfect view into space.

This remote location is home to a dozen different observatories and thus offers astronomers and astrophysicists from numerous different countries an infrastructure found almost nowhere else in the world. Of all the observatories located on the Roque de los Muchachos ridge, the Gran Telescopio de Canarias (or GTC for short) stands out the most: With 36 reflectors and a diameter of 10.4 meters, the silver-colored steel structure is one of the world’s largest reflecting telescopes. The GTC, which was opened in 2009 at a cost of 80 million euros and weighs around 300 tons, has already spotted more than 2,000 planets and discovered galaxies that are far away.

High-precision and accurate movement

Giant telescopes like the GTC operate with extremely high precision. Scientists observing the stars at night, and often into the early hours of the morning, depend on long exposure times, which means that the telescope has to be able to move with millimeter precision – an immensely challenging task given the enormous amount of weight involved.

                    The instrument rotator is an important high-precision mechanism that rotates the telescopic camera.

Schaeffler already successfully proved its expertise in this sector in 2015 when the company supplied a torque motor for a satellite observation station in Changchun (China), which is part of the National Astronomical Observatories belonging to the Chinese Academy of Sciences.

With expertise from the Industrial Drives division

Schaeffler Iberia contributed its specialist engineering expertise in the field of industrial drives to the latest project to take place on La Palma and was involved in developing an instrument rotator for one of the GTC’s focal stations, known as the Cassegrain Focal Station (CG-Set). IDOM, a Spanish company providing engineering and architecture services, was commissioned to develop this new CG set. Due to the positive experience during its long-standing collaboration with Schaeffler Iberia in various projects, IDOM decided to involve Schaeffler in the development of the instrument rotator drive.

The instrument rotator is an important high-precision mechanism in the telescope and controls the focal tracking and rapid positioning system that rotates the two-ton telescopic camera with outstanding evenness throughout the entire observation in order to ensure its perfect alignment with the heavens from start to finish. In this specific case, Schaeffler’s special drive solution not only had to ensure the system’s ability to precisely position the camera and regulate its speed, it also had to feature a convincingly compact and lightweight instrument rotator design.

Advantages of Schaeffler’s innovative solution

The drive solution used by Schaeffler is a so-called segmented, slotless RMF torque motor (similar to the type shown here). It is characterized by a highly dynamic yet very smooth motion and also operates very energy-efficiently.
The RMF torque motor type consists of segments. This design reduced the costs of transportation and mounting. In case of service, not the entire motor but only the affected segment has to be replaced.

Direct drive for highly dynamic yet very even motion

Schaeffler came up with a special solution that optimally suited the application’s requirements. Specialists from the company developed a segmented, slotless RMF torque motor for the drive of the instrument rotator and also provided assistance during the mounting process in order to determine the motor’s control parameters. The direct drive from Schaeffler Industrial Drives is characterized by its highly dynamic yet very even motion, which also takes place with a high level of energy efficiency. The special feature of the motor, which is more than two meters in diameter, is that it was developed and built based on a proven drive concept from machine tools for grinding operations that was adapted for the telescope.

This innovative solution from Schaeffler also has additional advantages. The segmented construction of the motor reduced the costs of transportation and mounting. What is more, the comparatively compact design facilitated the installation procedure and also helps to optimize the overall system’s performance and maintenance. A particularly important advantage is that only the affected segment – rather than the entire motor – has to be replaced when servicing is required.

Proof of extensive technological expertise

“This telescope project impressively demonstrates Schaeffler’s extensive technological expertise and innovative potential. With our unconventional drive solution, we have successfully created a special application that will allow mankind to accurately explore space and thus support groundbreaking international research. At the same time, our product provides a convincing level of added value for the customer when it comes to the performance, energy consumption, and future maintenance of the system,” explains Albert Monera-Llorca, President of the Industrial division for Schaeffler Spain and Southern Europe.