Diagonals

A high quality 90 degree star diagonal. For use with Refractor and SCT telescopes. Using this diagonal will ensure a comfortable viewing position when using your telescope.

45° Erecting Prisms include an internal flat mirror to reflect light to the telescope's 90° astronomical observing position; in this position the telescope's image is upright, but reversed.

Upgrades your existing cheap prism or mirror diagonal (ie the ones you commonly get bundled with telescopes) for vastly improved resolution at the eyepiece.

High quality 45° erect image diagonal. Corrects the image on refractors and SCT telescopes. The 45° angle will provide a comfortable viewing position when using your telescope terrestrially.

This 90° diagonal will provide corrected views on Refractor and SCT telescopes. High quality finish such as chrome barrel and high quality thumb screws for securing eyepieces.

This diagonal is for astronomers who prefer the convenience of 90-degree viewing but want to view a fully corrected image, ie the right way up and not mirror-reversed left to right.

Celestron’s 1-1/4" Erect Image Diagonals are an Amici prism design. This design allows you to look into the telescope at a 45° angle.

A Star Diagonal brings the eyepiece out at 90 degrees from the telescope tube, allowing comfortable viewing when the telescope is pointed at, or near, the zenith (i.e. directly overhead). The resulting image is the right way up, but is reversed from left to right.

1.25” RedCat Erecting Prism in silver for a perfect match to the new SpaceCat 51! Now you can use your SpaceCat during the day with correctly orientated views.

The ideal accessory for refractor telescopes
Perfect for nature observations
Easy orientation in the night sky

SCT Adapters thread onto the standard Celestron C8 back to allow use of standard 2" eyepiece accessories — such as our Everbrite diagonal mirror.

The RVO Horizon 90° Erecting Prism is a 1.25" diagonal that features a high quality Amici prism design.

High quality 2" star diagonal. Makes observing at high angles much more comfortable when using Refractor and SCT telescopes. Comes complete with the 2" - 1.25" adaptor so you can use both eyepiece sizes with this diagonal.

The Bresser Messier 2" Mirror Diagonal - 93% Transmission is very good diagonal mirror for refracting and Cassegrain telescopes with 2" focusers (and for the Explore Scientific and Bresser Messier telescopes with 2.5"- HEX focusers).

Use the iOptron 90° Dielectric Star Diagonal to place your head in a comfortable viewing position when your refractor or catadioptric optical tube assembly (OTA) is aimed at or near the zenith. Built with a dielectric hard-coated BK-7 glass mirror, the diagonal transmits more than 99% of the incoming light

All New 90 degree high quality Erecting prism With helical Focuser barrel.