ELT’s MICADO Filter Wheel Reaches a Pivotal Milestone
After eighteen years of design, testing, and meticulous engineering, the filter‑wheel mechanism destined for the Extremely Large Telescope (ELT) has been completed. Developed by the NOVA Optical‑IR group in Dwingeloo, this subsystem will become a core component of MICADO, the ELT’s near‑infrared super‑camera. The finished wheel has now been transferred to the German institute in Garching, where it will be integrated with the rest of the instrument.
Technical Highlights
The filter wheel comprises three massive discs, each measuring 1.5 metres in diameter. Embedded within the wheels are dozens of narrow‑band filters that transmit only very specific wavelengths, allowing astronomers to isolate faint spectral signatures with exceptional contrast. When the camera operates, the wheels will rotate rapidly to place the appropriate filter in the light path, enabling precise observations of exoplanets, isolated stars, and the structure of the Milky Way.
To preserve the delicate optics, the wheel will reside inside a cryostat—a specialized freezer that cools the assembly to 80 kelvin (‑193.15 °C). This extreme cold reduces thermal noise, a crucial factor for near‑infrared measurements. The cooling process is scheduled for early 2028, after MICADO is formally handed over to the European Southern Observatory (ESO).
International Collaboration
While many components were manufactured in‑house by NOVA, the project also relied on a network of partners across Europe and beyond. This collaborative approach ensured that the wheel meets the stringent performance standards required for the ELT’s unprecedented aperture. Project leader Ester Aranzana expressed her pride, noting that the subsystem will enable “scientific discoveries that were previously out of reach.”
Future Outlook
Following integration and a series of rigorous tests, MICADO is slated for shipment to Chile in 2030, where it will be installed on the ELT’s primary focus. Lead researcher Eline Tolstoy described the achievement as “a beautiful milestone,” emphasizing that the rotating filters will be essential during every observation night, delivering the sharp, high‑contrast images that the ELT promises.
With the filter wheel now in place, the astronomical community looks forward to the first data sets that will arrive a few years after commissioning. These observations are expected to push the boundaries of our knowledge about planetary systems beyond our own, the life cycles of stars, and the intricate dynamics of our galaxy.
Source: https://scientias.nl/belangrijk-onderdeel-grootste-toekomstige-telescoop-af-een-prachtige-mijlpaal/