The traditional right angle prism star diagonal has long held a reputation as a budget low-quality star diagonal. Given the extremely poor quality star diagonal prisms included with budget priced import refractors and domestic SCT telescopes, it is no surprise. Their prisms are horribly made, with incorrect face angles, non-flat rough optical surfaces, and poor coatings. Housings are crudely made from weak plastic, with poor angular accuracy and weak attachment of fittings. However, the prism star diagonal is capable of views which meet or exceed even the finest mirror star diagonals, and deliver them for lifetimes of use.
The Baader Planetarium T-2 Prism Star Diagonal is easily the finest prism star diagonal available today. The right angle prism is produced by Zeiss, and is the identical prism that Zeiss supplied for use with their exquisite APQ telescopes. The famous Baader 7-Layer Multi-Coatings ensure the image is bright and contrasty, and the oversized prism provides an oversized full clear aperture of 1.34” (34mm)! The precision machined aluminum housing provides a stress free mounting and precise location for the prism, unlike the typical weak plastic or crudely cast housings found on lesser diagonals. Extremely low scatter and high contrast images are the hallmark of this prism diagonal. The end result is a lifetime diagonal that matches or exceeds the brightness and image quality of the finest mirror star diagonals. Users of fine refractors over f/7 as well as SCT users have found that the Baader T-2 Prism Star Diagonal provides the sharpest and highest contrast images they have seen from any star diagonal, mirror or prism.
* PLEASE NOTE: The Baader T-2 Prism Star Diagonal incorporates standard T-2 threads at the input and output faces, and is provided as a basic component, without any input or output fittings. This permits the diagonal to be used as a compatible component along with the other Baader Planetarium T-2 accessories, like the VIP Modular Barlow or digital cameras. This also enables you to configure the diagonal to exactly suit your needs, and to fit 2" or 1¼” eyepieces, and focusers. The effective optical path length of the base T-2 Prism Star Diagonal is 47.5mm.