Baader 2" BBHS® Prism Adjustable Star Diagonal - 60 Years Vantablack® Edition

Vantablack® 310: An Ultra-Black Coating from Aerospace

The defining feature of this 60th-anniversary edition is the application of Vantablack® 310 coating to the internal housing surfaces. Originally developed for aerospace applications, this ultra-black material is exceptionally effective at absorbing stray light. Replacing the conventional matte-black coating, it suppresses internal reflections even more effectively and helps preserve image contrast and the finest details.

98-99% Reflectivity: The BBHS® Coated BaK4 Prism

At the heart of this diagonal is a BaK4 glass prism featuring Baader's Broad Band Hard Silver (BBHS®) coating. This sealed silver layer delivers 98-99% reflectivity across a vast spectral range of 390nm to 2000nm, resulting in noticeably greater brilliance and color fidelity compared to standard coatings. The prism also carries Baader's Phantom Coating® Group anti-reflection treatment. As a guideline, prisms are recommended for telescopes with focal ratios of f/6 to f/7 or slower, while mirror diagonals are often preferred for faster optical systems.

3-Point Alignment: A Precision-Adjustable Housing

The BBHS® prism rests stress-free on an adjustable cradle within its CNC-machined aluminum housing. This allows the diagonal to be precisely collimated, a critical feature for building binocular telescopes or ensuring perfect alignment in any demanding optical system. Each diagonal leaves the factory with its 3-point alignment perfectly set on an optical bench, ensuring the optical and mechanical axes are matched. While you can adjust it, doing so voids the warranty on the factory collimation, so all other error sources like a tilted focuser should be eliminated first.

The 2" ClickLock Clamp and Modular Connections

Holding your eyepiece or camera securely is the Baader 2" ClickLock clamp, which grips accessories firmly on three sides with a simple 20° twist. This mechanism prevents tilting and ensures repeatable, centered alignment every time. The diagonal includes a 2" nosepiece with a Safety-Kerf to prevent it from slipping out of the focuser. Its modular design offers multiple connection threads, including M48, M55, and a 2"/SCT thread on the telescope side, providing versatile integration into your imaging train.

Made in Germany in a Collector's Beechwood Case

This anniversary edition is a testament to German engineering. The housing components are made on Baader's own CNC machines, the optics are polished and coated in Germany, and final assembly, adjustment and quality testing are carried out at Baader's facility in Mammendorf. To complete the collector's package, each diagonal is delivered in a high-quality, black-lacquered beechwood box, specially manufactured in Austria from locally sourced wood.

Vantablack® Edition vs. Standard BBHS® Prism Diagonal

The optical and mechanical systems of this limited edition (#2456118B) and the standard Baader 2" BBHS® Prism Diagonal (#2456118) are identical. Both feature the same adjustable housing, BaK4 prism, BBHS® and Phantom Coating® Group coatings, and ClickLock clamp. The difference is on the inside: the internal coating. The anniversary edition also comes in a beechwood collector's box.

• Vantablack® Edition (#2456118B): Uses Vantablack® 310, originally developed for aerospace, on the internal housing surfaces for even more effective suppression of stray light and internal reflections.
• Standard Edition (#2456118): Uses a conventional matte-black coating inside the housing.