Tele Vue 90º Enhanced Aluminum Diagonal - 1.25"

Enhanced Aluminum Mirror Coatings for Bright Views

At the heart of this diagonal is a mirror with Tele Vue's enhanced aluminum coatings. This multi-layer coating system achieves 96% reflectivity across the visual spectrum, ensuring that the maximum amount of light from your telescope reaches your eye. The direct visual benefit is a brighter image, which is especially important when observing faint deep-sky objects or fine planetary detail at high magnification.

Unlike some mirror coatings that can introduce a slight color cast, Tele Vue's enhanced aluminum is formulated for color neutrality. This means the double stars, planetary bands, and subtle nebular hues you see are true to life. It renders a clean, honest image, allowing the optical quality of your telescope and eyepiece to define the view.

Robust and Precise Diagonal Housing

The diagonal's body is machined from solid aluminum to maintain precise alignment of the internal mirror. This rigidity prevents flexure, which can lead to image shift or astigmatism, especially when using heavier eyepieces or barlows. The 90-degree angle provides a comfortable viewing position for any object more than a few degrees above the horizon, reducing neck strain during long observing sessions.

This diagonal is not a dielectric, which represents a specific design trade-off. While dielectrics offer slightly higher reflectivity and surface durability, this enhanced aluminum model provides its high performance at a more accessible price point and lighter weight. For visual use, the 2-3% difference in light transmission is often imperceptible, making this a practical choice for many observers.

Secure, Non-Marring Eyepiece Clamp

Tele Vue has engineered this diagonal with a non-marring brass clamp ring to hold your 1.25" eyepieces. Unlike simple set screws that can scratch and dent your eyepiece barrels, this mechanism provides a uniform grip around the circumference of the barrel. The result is a more secure connection that preserves the finish of your valuable eyepieces and ensures perfect alignment with the optical axis every time.

Contrast-Boosting Internal Baffling

To maximize image contrast, the interior of the diagonal is fully blackened and threaded with anti-reflection baffles. These features are designed to trap any stray light that enters the diagonal, preventing it from reflecting off internal surfaces and washing out the image. This attention to detail becomes apparent when observing bright objects like the Moon or Jupiter, where it helps preserve fine, low-contrast details against a dark background.

Imagine using this diagonal with a quality 80mm refractor to view the cloud belts of Jupiter. The 96% reflectivity ensures the planet and its moons appear bright and crisp. As you push the magnification, the internal baffling keeps the background space black, making it easier to spot the subtle festoons and barges within the Jovian atmosphere that a less-optimized diagonal might obscure.

Choosing Your Tele Vue Diagonal

Tele Vue offers several 1.25" diagonals, and the choice depends on your priorities. The 90º Enhanced Aluminum model is the standard for high-quality visual observing where brightness and color fidelity are key.

• vs. Tele Vue Everbrite Dielectric Diagonal (DPC-1250): The Everbrite diagonal offers 99% reflectivity and a more durable, easier-to-clean mirror coating. It is the choice for observers who want the absolute maximum light transmission and longevity. However, the Enhanced Aluminum diagonal provides nearly identical visual performance for a lower investment, making it an excellent value.
• vs. Tele Vue 60º Everbrite Diagonal (DPC-6012): The 60º diagonal is designed for specific applications where the telescope is mounted very low, such as on a Tele-Pod mount for seated observing. For general use on most equatorial or alt-az mounts, the 90º orientation of the Enhanced Aluminum model is more comfortable.