Levenhuk Ra 1.25" Star Diagonal, 99% Reflection angle: 90°. Barrel diameter: 1.25" Levenhuk Ra 1.25" Star Diagonal, 99% is a diagonal mirror with a 1.25" barrel diameter and 90-degrees reflection angle. The mirror has a special 99% reflection power dielectric coating, so it provides high-quality views. Star diagonal is commonly used with refractors or catadioptric telescopes for observing objects high above the horizon. It produces an upright but left-to-right mirrored image. Levenhuk Ra 1.25" Star Diagonal, 99% is made of anodized aluminum so it is lightweight. A 1.25" adapter is included in the kit to make using this model even more comfortable. Reflection angle, °: 90 Coating: dielectric, 99% reflectivity Barrel diameter: 1.25" Shell: anodized aluminum