Dielektryczne zwierciadło zenitalne z kwarcu z 99% odbiciem 2"

If what you are looking for is the highest achievable brightness, contrast and sharpness during critical observations with high-end instruments, William Optics 90° 2" mirror Dielectric star Diagonal is your choice. A premium product at a discounted price!

Features:
Ultra High Dielectic 99% reflecivity
Precision 1/10 lambda surface with 10mm-thick mirror
2'' -1.25'' adapter with brass clamping ring
Inside diameter (48mm): threaded to fit a variety of filters
Weight: 470g
comes with free sct thread adapter

Illustration similarly