Baader M68 Extension Tube – 7.5 mm

Baader M68 Extension Tube – 7.5 mm

Description
The Baader Planetarium M68 – 7.5 mm extension tube is a precision component designed for professional optical setups where precise backfocus adjustment and maximum mechanical rigidity are required.

In astrophotography and spectroscopy, even the smallest amount of flexure or tilt between the telescope and the camera can cause image degradation, apparent miscollimation, or field distortion. This issue is especially critical when using long, heavy accessories such as telecentric systems or the Fluorite Flatfield Converter (FFC), which apply significant leverage to the focuser. Slip-fit connections, even with brass compression rings, cannot always prevent these micro-shifts.

The M68 x 1 thread standard, widely used in high-end instruments (including Zeiss systems), provides a solid screw coupling that completely eliminates play and tilt. This Baader extension tube, machined from high-quality aluminium, ensures a perfect fit, wide contact surface, and uncompromising stability.

With its 7.5 mm optical path, it allows precise distance tuning for:

• Perfectly aligned eyepiece projection setups

• Achieving optimal magnification with the FFC in planetary imaging

• Telecentric systems combined with H-alpha filters for high-resolution solar observation

• Meeting exact backfocus requirements in imaging trains

The internal surface is carefully blackened to suppress internal reflections and maintain maximum contrast, even under bright-light conditions. Precision machining ensures smooth assembly, no binding, and perfect concentricity with the optical axis.

This extension tube can be used alone or in combination with other M68 extensions to reach the desired optical length. It integrates seamlessly into Baader’s modular M68 system, offering compatibility with instruments and accessories using this thread standard, including adapters to other formats (Astro Physics 2.7", M60 Vixen, M56 Synta, etc.).

Technical specifications

• Manufacturer: Baader Planetarium

• SKU: 2458212

• EAN code: 4047825036551

• Adapter family: M68 system

• Optical length: 7.5 mm

• Telescope-side external thread: M68 x 1

• Accessory-side internal thread: M68 x 1

• Clear aperture: 62 mm

• Outer diameter: 76 mm

• Weight: 0.03 kg

• Material: precision-machined aluminium

• Internal finish: matte black anti-reflective coating

• Usage: extension for eyepiece projection, FFC, or telecentric system

• Compatibility: Baader M68 and Zeiss systems