Built to the same precise specifications as the original Zeiss design, the Alpine Astronomical Baader 90° T-2 Star Diagonal Prism delivers high-quality performance that discerning astronomers demand.

It is made with BAK4 prism glass that is treated with Broadband Hard Silver (BBHS) coatings, dielectric coating, and the proprietary Phantom Group anti-reflection multi-coatings. These work together to boost light transmission to greater than 99% for minimal light loss and diffraction. The broadband coatings uniformly transmit all wavelengths of light between 390 and 2000nm for accurate color rendition and enhanced clarity. As a mirror diagonal, the views through it will appear right side up, but vertically reversed.

The prism is stripped to just the housing, making it ready for complete customization with any of Alpine Astronomical's T-2 Astro modular accessory system components. It has male T-2 threads on one side and female T-2 threads on the other. This presents a very short optical length for easy adaption to any telescope, photography rig, or binoviewer. With these standard T-2 mounting threads on each side, you can attach a wide array of nosepieces, holders, extension tubes, filter holders, and adapters for both visual and photographic applications.