Baader T-2 Prism Star Diagonal

The T-2 system is a standardized thread (M42x0.75) that allows you to screw this diagonal directly into other Baader components or adapters. It means you can build a custom optical train—like connecting a camera or specific eyepiece holders—without relying on standard compression rings or nosepieces.

Prism diagonals are generally preferred for their durability and contrast, as the glass surfaces are less prone to degradation over time compared to mirror coatings. They are particularly excellent for high-resolution planetary and lunar observing where maintaining image contrast is critical.

No, this is the diagonal body only. It is designed as a modular component, so you will need to purchase the specific T-2 nosepiece and eyepiece holder that fit your telescope and eyepieces separately.

While prism diagonals work well with many systems, they can introduce some spherical aberration in very fast telescopes (f/5 or faster). If you are using a very fast refractor, you may want to ensure your optical train is perfectly aligned or consider if a mirror diagonal better suits your specific focal ratio.

This unit is significantly more robust than the plastic or thin-metal diagonals often included with entry-level telescopes. It is machined to tight tolerances, ensuring that once you align your optical train, it stays rigid and secure throughout your viewing session.