The last three-mirror anastigmat?

Multimirror reflective optical systems have seen significant development in the past 20 years. Advances in computer-aided design, fabrication, and alignment have produced ever higher performance optical systems in response to ever more demanding requirements. From a purely aesthetic standpoint, three-mirror optical forms hold a unique position in performance/complexity space: three mirrors are available, and three aberrations need to be corrected (spherical, coma, and astigmatism).