William Optics 2" Quartz Dielectric Coating Diagonal with SCT Adapter

If what you are looking for is the highest achievable brightness, contrast and sharpness during critical observations with high-end instruments, WO 90° 2" mirror Quartz Dielectric star Diagonal is your choice. We recommend this product for everyone who only wants the best.

This package consists of a refractor type quartz diagonal plus an SCT adapter (part # D-SCT-TA). You can easily use this on any refractor telescope with a standard 2" barrel, or on any SCT telescope with a standard SCT thread. To switch from a refractor diagonal to an SCT diagonal, simply unscrew the 2" nosepiece and screw on the included SCT adapter ring.

Top-Notch Performance and Brightness
• Dielectric coating allows 99% reflectivity.
• 10mm thick substrate flat for optimal image stability.
• Quartz being a harder material, it can be polished to a higher accuracy. Quartz also boasts one of the lowest expansion rate compared to other materials.
• Accurate design guarantees constant alignment. No further alignment needed.

Meticulous Craftsmanship
• 2" to 1.25" eyepiece adapter included.
• Lock screw for eyepiece/adapter.
• Big, knurled thumbscrews easy to turn even with gloves on.

Strikingly Beautiful
Patented, elegant design.
High-quality machining out of the best aluminum.
Internally antireflection threaded for highest contrast.

Superbly Constructed
• Compression rings (both on diagonal and adapter) to prevent barrels-marring.
• Internal safety stop prevents 2" barrels from hitting the mirror.

SCT Adapter Included With Each Diagonal
Also included with this diagonal is an SCT ring (William Optics part # D-SCT-TA) that makes your diagonal work on SCT telescopes or William Optics' ZS66 series as well! Get one diagonal, use it on ANY telescope! This SCT adapter sells for $35 by itself but is included in this diagonal package! Note that this adapter will work with the most recent ZS66 Series telescopes sold in the blue, white, or orange OTA versions. It will not work with the older black tube ZS66 Petzval Series.

Why W.O. diagonals do not feature an Adjustable alignment system?
Having an adjustable alignment system is an admission that the diagonal can go out of collimation due to poor mechanical construction. Thanks to the patented design of WO diagonals, you will always have a diagonal that performs perfectly like the first day you got one!

Features:
• Ultra High Dielectric 99% reflectivity
• Highest precision surface with 10mm-thick mirror.
• 2"-to-1.25" adapter with brass clamping ring.
• Inside diameter (48mm): threaded to fit a variety of filters.
• Weight: 470 g