Celestron 2” XLT Mirror Diagonal

Celestron 2” XLT Mirror Diagonal – Precision-Engineered for Bright, High-Contrast Views

A high-quality diagonal is one of the most important yet often overlooked upgrades you can make to your telescope. The Celestron 2” XLT Mirror Diagonal is designed to be a true workhorse accessory—delivering exceptional optical performance, enhanced light transmission, and precision alignment for consistently sharp, high-contrast views of the night sky.

Whether you're scanning the Milky Way for faint nebulae or enjoying crisp lunar detail, this diagonal maximises the optical potential of your telescope—especially when paired with large 2” eyepieces.

Why a 2” Diagonal Matters

If you're aiming to capture more light and reveal finer detail, especially in deep-sky observing, a 2” star diagonal is essential. Compared to standard 1.25” models, a 2” diagonal allows a wider light path from your telescope to reach your eye, enabling the use of wider-field 2” eyepieces.

This is particularly beneficial for:

• Observing faint galaxies, nebulae, and star clusters

• Maximising the field of view for rich-field astronomy

• Improving image brightness at low magnifications

The larger barrel diameter ensures that more of your telescope’s light cone is preserved, giving you brighter and more immersive views—especially valuable when observing objects with low surface brightness.

Precision Machined for Perfect Optical Alignment

The Celestron 2” XLT Mirror Diagonal is built with premium materials and tight tolerances, ensuring long-lasting performance and optical precision. The CNC-machined housing maintains precise optical alignment, which is critical for preserving image quality across the field of view.

Each mirror is interferometer-tested to deliver an impressive surface accuracy of 1/10 wave or better. This high level of optical flatness ensures that the diagonal introduces no distortion or degradation to your telescope’s native performance.

High-Performance XLT Optical Coatings

Celestron applies its renowned XLT (Extra Low Transmission) optical coatings—the same coatings used on its flagship telescopes—to the diagonal’s mirror surface. These multi-layer dielectric coatings:

• Increase reflectivity

• Enhance image contrast

• Minimise light loss and scatter

The result is a bright, high-contrast image that reveals fine detail in celestial objects, whether you're viewing planets, the Moon, or deep-sky targets.

Seamless Integration with SCT Telescopes

This diagonal is specifically designed for Schmidt-Cassegrain telescopes (SCTs) and threads directly onto the rear cell for a secure, stable connection. This design eliminates the need for additional adapters and reduces flexure in your optical train.

To use 2” eyepieces, simply insert them into the diagonal’s 2” barrel. If you prefer to use standard 1.25” eyepieces, the included 2” to 1.25” adapter allows quick and easy conversion. A built-in thumbscrew ensures your eyepieces stay secure during use.

Durable, Portable, and Ready to Use

When you're not observing, keep your diagonal safe in the included aluminium storage case. This protective case shields the diagonal from dust, moisture, and knocks during transport—ideal for astronomers on the move.

Key Features:

• 2” mirror star diagonal with high-performance XLT coatings

• 1/10 wave or better mirror surface accuracy, verified by interferometer testing

• Precision CNC-machined housing for perfect optical alignment

• Threads directly onto Schmidt-Cassegrain telescope rear cells

• Compatible with 2” and 1.25” eyepieces (adapter included)

• Bright, high-contrast views ideal for both planetary and deep-sky observing

• Supplied in a protective aluminium storage case

A Smart Upgrade for Serious Observers

If you're still using a basic diagonal that came with your telescope, upgrading to the Celestron 2” XLT Mirror Diagonal is one of the most effective ways to boost performance. Experience the difference in brightness, clarity, and contrast—whether you're a seasoned astronomer or just starting your celestial journey.

Unlock the full potential of your SCT telescope with this high-quality diagonal designed to meet the demands of serious visual astronomers.

Order yours today and enhance every observing session with brighter, sharper, more detailed views.