When it comes to long-range, multispectral optical systems, large mirrors play an integral role. They take many shapes — spherical, aspheric, parabolic, or freeform — and are used for a wide spectrum of light, including visible, UV, and IR. Over the last 10 years, optical systems with reflective elements have been used by system integrators in the defense and aerospace industries, in surveillance and monitoring, and in certain commercial applications. For example, large mirrors may be integrated into the optical systems of large unmanned aerial vehicles (UAVs) in long-distance aerial monitoring of agricultural field temperature using IR. In this webcast, we will discuss challenges in the optical design and manufacturing of refractive optics, while presenting relevant case studies.