Best Telescope Diagonals of 2025

The SVBONY SV188P Dielectric Mirror Star Diagonal is designed for astronomical viewing with its super flat mirror and over 99% reflective surface. Its 1.25 inches nosepiece fits 1.25 inches telescopes and accepts standard 1.25in filters, eyepieces, Barlow lenses and other accessories with a 1.25in insert barrel. The 90 degree viewing angle provides a more comfortable viewing angle for observing objects overhead. Additionally, the diagonal corrects the upside down and left right reversed image, and its built-in brass ring and thumbscrew accessories avoid eyepiece rotation during adjustments without scratching your eyepieces barrels.

The SVBONY Diagonal Mirror enhances your telescope experience with its 1.25-inch diameter, making it compatible with standard telescopes and eyepieces. The aluminum construction ensures high light transmittance, delivering clearer and brighter images. Additionally, the brass compression ring protects against surface damage, allowing you to use your eyepiece without worry. With support for 1.25-inch filters, this diagonal mirror offers versatility for a range of observations, giving you more options for your stargazing adventures.

The SVBONY 1.25 inches 90 Degree Dielectric Mirror Diagonal is a great addition to your refracting or catadioptric telescopes. Its 90% reflectivity flat mirror helps reduce light loss and provides a clear and sharp view. The diagonal has a standard 1.25 inches diameter and a 90-degree viewing angle, making it compatible with eyepieces and barlow lenses. The full metal body with a dust cover is durable and ensures a prolonged life.

The SVBONY Diagonal Mirror enhances your stargazing experience with its 45-degree correct-image prism, ensuring you see sharp, upright images without any left-right inversion. Its innovative design features a durable ABS plastic housing and precision-machined aluminum barrels, providing both strength and stability. The inclusion of a brass lock screw and compression rings allows for secure attachment, protecting your telescope from scratches and damage. Additionally, it supports 1.25-inch filters, giving you the flexibility to customize your observations for a more versatile viewing experience.

The Celestron Star Diagonal enhances your telescope experience by providing clear and bright views. With its 90° viewing angle, you can observe comfortably for longer periods, particularly through refractor and cassegrain telescopes. The diagonal features 58 layers of dielectric coatings, ensuring that over 99% of the light collected reaches your eyepiece, resulting in stunning images. Additionally, the twist-lock mechanism secures your eyepiece in place, promoting better optical alignment and reducing any potential image distortion. This diagonal also includes a step-down adapter, making it compatible with both 2” and 1.25” eyepieces and accessories for added versatility.

The SVBONY SV223 Diagonal Mirror offers a secure clicklock mechanism that ensures your eyepiece stays firmly in place while you observe the stars. With its impressive 99% reflectivity, this diagonal mirror enhances image clarity, allowing you to see celestial objects in vibrant detail. The high-quality aluminum construction not only makes it lightweight but also durable, ensuring longevity. Additionally, the 90-degree design improves your viewing experience by providing a comfortable angle for extended observation sessions. Enjoy stability, clarity, and convenience with this essential astronomical accessory.

This 2-inch diagonal has a 99% reflectivity mirror star diagonal that provides a comfortable 90-degree view from your refractor. It fits standard 2-inch diameter focus tubes and can use both 2" (50.8 mm) and 1.25" (31.75 mm) eyepieces, which are protected by non-marring brass compression rings. The dielectric surface does not age like aluminum, ensuring long-lasting high-quality optics.

The Astromania 1.25" 90-Degree Diagonal Mirror is a useful accessory for refractor and Cassegrain telescopes, offering a comfortable viewing orientation as you observe from above. It features a filter thread for any 1.25" filter and accepts standard 1.25" eyepieces. The mirror has a protective coating to ensure a long life and a metal barrel that provides secure seating in the focuser. With its wide 90 degree angle, you can view a correct image from a refractor telescope stand and just look down with a comfortable angle.

The SVBONY 90 Degree Diagonal enhances your stargazing experience by allowing for comfortable viewing angles. Its clever 90-degree design makes it easier to observe celestial objects without straining your neck. Additionally, the extinction thread prevents unwanted stray light, ensuring that your observations are clear and high-quality. You can easily connect filters thanks to its 1.25-inch threading, allowing for versatile use with different eyepieces. Finally, the locking mechanism provides a secure fit for your eyepiece, preventing any accidental slips during your observations.

The SVBONY Star Diagonal enhances your stargazing experience with its 90-degree design, allowing for comfortable viewing angles. It features a clicklock locking mechanism that ensures quick and secure attachment of your eyepiece, so you won’t have to worry about it slipping during use. The diagonal is equipped with a high-quality optical flat mirror that boasts a 99% reflective coating, providing you with bright and clear images. Made from lightweight aluminum, it also includes internal baffling to reduce reflections, ensuring you get the best contrast while observing celestial objects.