The Celestron 1.25-inch Erect Image Diagonal utilizes an Amici prism design to allow comfortable observation through a telescope at a 45° angle. Unlike a standard star diagonal which may only correct the image up-and-down, this diagonal mirror produces an image that is fully upright and correct from left-to-right.

Terrestrial Viewing Made Easy

Astronomical telescopes naturally produce an inverted or mirror-reversed image. While this doesn't matter for deep-sky observation, it can be disorienting for lunar and planetary viewing, and makes daytime use impossible. This Celestron erect image diagonal solves that problem. Its internal prism acts as an erecting lens, correcting the image so that what you see in the eyepiece matches the naked-eye view, making it perfect for daytime activities. For users looking for an "erecting eyepiece" effect, this is the correct accessory to achieve that.

Construction and Compatibility

• Amici Prism Design: The high-quality internal prism provides a sharp, correctly oriented image, a key feature of this erect image diagonal.

• Standard 1.25" Barrel: This telescope diagonal fits into any telescope focuser or visual back that accepts standard 1.25" eyepieces.

• Telescope Use: This is an ideal star diagonal for telescope models like refractors and Schmidt-Cassegrain telescopes (SCTs). It is generally not compatible with Newtonian reflector telescopes due to insufficient back focus.

Key Features

• Provides a 45° viewing angle for comfortable observation with your telescope.

• Produces a fully erect and correctly oriented image, making it an ideal erecting lens.

• The high-quality Amici prism acts as a premium diagonal mirror for sharp views.

• This Celestron star diagonal fits standard 1.25" focusers and visual backs.

This product is covered by Celestron's 2-Year Warranty. 

Why Shop Celestron from OpticsCentral?

OpticsCentral is a Premier Select Dealer for Celestron in Australia, offering expert advice, local warranty support, and access to genuine spare parts. As an authorised Celestron Premier Select Dealer, we provide local warranty support and fast turnaround on repairs—giving you peace of mind with every purchase.

About Celestron

Celestron was founded by Tom Johnson whose first telescope design was a simple 6-inch reflector, built for his young son. He gradually progressed to making larger scopes in more sophisticated designs. Today, the Celestron company is an industry leader in designing and manufacturing optical equipment including telescopes (computerised and non-computerised), binoculars, spotting scopes and its accompanying accessories. Celestron's legacy spans 50 years, and has grown to enjoy recognition from amateurs to serious astronomers globally. The company seeks to remain innovative by growing its product offerings, while supporting science education around the world.

Product Code: CLS-94112-A