If what you are looking for is the highest achievable brightness, contrast and sharpness during critical observing with high-end instruments, then the Williams Optics 2", 90° dielectric mirror star diagonal is the right choice for you. A premium product at a discounted price!
Ultra high 99% dielectric reflectivity
Precision 1/10 lambda surface with 10mm thick mirror
2'' -1.25'' adapter with brass clamping ring
48mm inside diameter, threaded to fit a variety of filters
470g in weight
comes with free SCT thread adapter
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