Upgrade your existing star diagonal to this premium one and enjoy brighter, sharper images without purchasing an entirely new telescope. This star diagonal reflects the telescope�s light path 90� to provide a more comfortable viewing angle. In addition, the glass has 58 layers of dielectric coatings, which provide an over 99% reflective surface, delivering the maximum amount of light to the eyepiece. This 2� star diagonal has the added benefit of allowing you to use larger 2� eyepieces with your telescope, providing a wider field of view, or standard 1.25� eyepieces with the stepdown adapter. The twist-lock eyepiece holder secures eyepieces while keeping them centered in the diagonal, thus providing best opto-mechanical alignment between the telescope and eyepiece. Unlike traditional thumb screws, the twist-lock cannot scratch or engrave the barrel of your eyepieces. The diagonal has an integrated 2� barrel stop that prevents 2� accessories with long barrels from damaging the mirror. All the diagonal�s mechanical parts are made of machined black anodized aluminum, except the twist lock rings, which are orange anodized for visibility. The interior of the Schmidt-Cassegrain adapter and 2� barrel are glare threaded and painted flat black to prevent glare. With all its features and these high-end finishes, the Celestron Dielectric Star Diagonal, 2� with Twist-Lock is one of the highest quality 2" star diagonals that Celestron has ever offered.This diagonal also comes with two interchangeable barrels to provide flexibility in connecting the diagonal to a wide variety of telescopes without the need for additional adapters. For telescopes, like refractors, which accept 2� barrels in their focuser, a standard 2� barrel is included. For Schmidt-Cassegrains (SCTs) that use a threaded connection to the focuser, a barrel with SCT threads is included. Both barrels thread onto the diagonal housing, providing a secure connection to the diagonal.Features- Enjoy better views through your telescope with this premium diagonal featuring diffraction-limited optics and dielectric coatings- Provides a 90� viewing angle, perfect for more comfortable viewing through refractor and Cassegrain-type telescopes- 58 layers of dielectric coatings provide an over 99% reflective surface, ensuring the maximum amount of light collected by the telescope reaches the eyepiece- Twist-lock keeps the eyepiece centered in the diagonal to provide better optical alignment- Includes a stepdown adapter, so the diagonal accepts eyepieces, Barlow lenses, threaded filters, and other accessories in both 2" and 1.25" sizes- Two interchangeable adapters allow you to switch between a Schmidt-Cassegrain thread adapter and a 2" barrel adapter so you can use this diagonal with a wide variety of telescopesSpecificationsDiagonal size: 50.8mm (2")Diagonal type: MirrorGlass material: BK7Coatings: Dielectric, 58 layersReflectivity: Over 99%Optical quality: Diffraction limitedEyepiece holder: 2", Twist-Lock2"-to-1.25" Stepdown adapter: Included, Twist-LockCompression ring: Yes, dual rings for 2" eyepiece holder and single ring for 1.25" stepdown adapterHousing construction: Machined aluminum black anodizedBarrels: Comes with 2" barrel (for connection to 2" focusers) and SCT adapter (for connection to SCTs)Barrel interior: Glare threaded and painted flat blackThreads for filters: 2" barrel and 1.25" stepdown adapter have 2" filter threadsDimensions: 152.4mm x 76.2mm x 101.6mm Weight: 538.6 g (with stepdown adapter)