Unlocking the Secrets of the Universe with Precision Adaptive Optics
What you’ll learn:
- Why adaptive optics are important in astronomy.
- How adaptive optics work.
- What are the important supporting technologies in adaptive optics?
Penetrating deep space to unlock the secrets of the universe, the ESO Extremely Large Telescope leverages adaptive optics to correct for atmospheric disturbances so that it can extract more light, achieving higher-resolution imaging. Perched atop Cerro Armazones in Chile’s Atacama Desert at an altitude of about 3,000 meters, the ESO Extremely Large Telescope captures light, which is reflected from the primary to a secondary, adaptive mirror. The mirror physically deforms to recreate the proper light wavefront.
Microgate provides the control systems that mechanically deform the mirror to manipulate the observed wavefront, which corrects for atmospheric disturbances and improves the image quality. Contactless, linear voice-coil motors are used to make it happen.
The adaptive mirror is 2.4 m in diameter and 1.9 mm thick. The voice-coil motors are driven by a precise current driver and a series of co-located permanent magnets glued to the back of the mirror that deform the glass.
The 5,316 motors used have an inter-axis distance, or pitch, of about 30 mm, and the adaptive mirror “floats” on the magnetic field generated by the voice-coil motors. A dedicated control current locally deforms the mirror to correct the shape using an array of highly sensitive capacitive position sensors with an accuracy in the nanometer range.
Operating at a frequency of about 100 kHz, Microgate’s control mechanisms can completely redefine the shape of the mirror in 1 ms.
Addressing the energy challenges to achieve the precision, Microgate chose the Vicor DCM3623 series DC-DC power module, which is mounted on the underside of the gas-cooled cold plate, with each DCM3623 driving up to 36 motor channels. The Vicor power modules offer high power density and efficiency, with fast transient response and low electromagnetic noise that can disturb the focusing system.
