Explore Scientific 99% Reflective 2" Diagonal

A 2-inch dielectric-coated star diagonal that reflects 99% of incoming light — significantly brighter than standard aluminum or enhanced-aluminum mirrors that typically reflect 88–94%. The first-surface dielectric coating delivers the brightest, highest-contrast views your telescope can produce.

The double-taper insert barrel slides smoothly into any 2-inch focuser and locks securely — the wider taper section prevents the diagonal from falling out even if the set screw loosens. A compression ring lock holds eyepieces firmly without marring their barrels. Includes a 1.25-inch adapter with its own compression ring, so every eyepiece in your collection fits.

Key Features

• 99% first-surface dielectric coating for maximum brightness
• Double-taper insert barrel for secure, smooth focuser fit
• Compression ring eyepiece lock — no set screw marks on barrels
• 1.25" adapter and dust covers included
• Lightweight construction: 1.0 lb (0.45 kg)

Ideal For

• Visual observers upgrading from a stock diagonal — the jump from 88% to 99% reflectivity is immediately noticeable on faint objects
• Refractor and SCT owners — drop-in 2" diagonal replacement for any telescope with a 2" focuser