Imagine staring at the stars, only to have your view blurred by Earth's pesky atmosphere. It's not just a problem for stargazers; astronomers face the same frustration, battling clouds, atmospheric interference, and the invisible culprit of turbulent air mixing at different temperatures. But here's where it gets fascinating: scientists have devised a clever solution using shape-shifting mirrors, and a recent video by Huygens Optics reveals the intricate workings of this technology.
At the heart of this system lies the deformable mirror, a marvel of engineering. Picture a rigid backplate supporting a grid of tiny linear actuators, sandwiched between it and a thin sheet of quartz glass that forms the mirror's reflective surface. You might think glass is too stiff to bend under the gentle force of these actuators, but here's the surprising part: even the most rigid materials can flex when measured with precision. Under an interferometer, the glass visibly bends when squeezed by hand, and the actuators generate enough deformation to correct optical distortions. These actuators, crafted from copper wire coils beneath magnets glued to the glass, push and pull the mirror with adjustable force by varying the current's polarity and strength. Flexible silicone pillars, running through the coil centers, securely hold each magnet to the backplate.
Interestingly, when a square wave is applied to an actuator, the mirror vibrates like a speaker, producing an audible tone—a testament to its flexibility. However, a Fizeau interferometer provides more precise measurements, confirming the mirror's ability to alter the concavity, tilt, and coma of incoming light wavefronts. And this is the part most people miss: in the initial design, adjacent actuators could cancel each other out if they moved in opposite directions. To address this, [Huygens Optics] replaced the glass frontplate with a thinner sheet of glass-ceramic (a material he’s experimented with before: https://hackaday.com/2025/06/28/making-optical-glass-from-ceran-stovetops/), allowing actuators to work independently and shape the mirror in more intricate ways. For instance, the mirror’s center could be convex while the rest remains concave.
This isn’t [Huygens Optics]’s first foray into deformable mirrors (https://hackaday.com/2020/06/27/variable-mirror-changes-shape-under-pressure/), but it marks a significant leap in precision. If you don’t require such high accuracy, controlled thermal expansion (https://hackaday.com/2022/07/25/a-tiny-forest-of-resistors-makes-for-quick-and-dirty-adaptive-optics/) offers a simpler alternative. Conversely, pushing this technology to its limits enables breathtaking high-resolution images of the sun (https://hackaday.com/2025/06/01/adaptive-optics-take-clearest-pictures-of-the-sun-yet/).
But here’s the controversial question: As adaptive optics become more accessible, will they democratize astronomy, or will they widen the gap between professional and amateur stargazers? What do you think? Share your thoughts in the comments below!
