The William Optics Dura-Bright 2" diagonal is a high quality 90° mirror-type star diagonal with dielectric coatings for 99% reflectivity, giving ultra-high contrast and resolution for planetary, lunar and binary star observation.
The high precision 12mm-thick mirror substrate is polished to 1/12th lambda accuracy for optimal image quality. Meticulously CNC-machined with internal anti-reflection baffling and carbon fibre side plates, the Dura-Bright 2" diagonal is an exceptionally well constructed piece of equipment.
The compression rings on both diagonal and the included 2" - 1.25" adapter prevent eyepiece barrels from marring. The large knurled thumbscrews are easy to operate when wearing gloves. The internal safety stop prevents 2" barrels from hitting the mirror.
The Dura-Bright 2" diagonal is threaded for 48mm (2") filters.