Monolithic Schmidt-Cassegrain
Recently a video from Huygens Optics took the internet by storm, at least in certain circles. It details how Rik ter Horst made a monolithic Schmidt-Cassegrain telescope and a novel implementation of a solid catadioptric design form, instantiated in a monolithic block of fused silica.
The video is extremely detailed and there is no point in going over it in the written word when a picture is worth a thousand words so take a cup of coffee and enjoy 24 minutes deep dive into the physics of optics and telescope design.
If you are still reading the short of it is that Monolithic Telescopes are extremely robust and compact imaging systems designed to provide high-quality imaging from nano-satellites, UAVs, laser target designators, and other gimbal mounted laser systems, there is a requirement for a telescope that is extremely compact and immune to environmental factors which can cause optical aberrations and unwanted beam divergence.
The monolithic telescope's compact design allows for smaller imaging systems without sacrificing performance. Monolithic telescopes can be fitted onto smaller spacecraft or aerial gimbals at a similar level of performance to conventional Cassegrain telescopes.
Monolithic Telescopes can eliminate the requirement for in-flight focusing, as well as vibration and temperature variations. Also can achieve optical tolerances that are impossible to achieve with traditional two-mirror Cassegrain telescopes. Because of the tighter tolerances, more extreme optical surfaces can be used in the design, allowing for very high focal length to physical length ratios while still preserving diffraction-limited performance.
