Baader Planetarium 4x Telecentric Barlow Lens for Solar H-alpha Imaging (M68 Thread)

High-resolution solar imaging demands uncompromising optical precision, yet standard Barlow lenses often introduce chromatic aberration and field curvature that degrade fine details like prominences and granulation. The Baader Planetarium 4x Telecentric Barlow Lens solves this by delivering a truly telecentric light path with apochromatic correction, ensuring uniform magnification and sharpness across the entire field. Engineered for solar H-alpha work, spectroscopy, and planetary imaging, this 4-element lens maintains a flat, diffraction-limited image circle of 36 mm, making it the critical link between your telescope and camera or eyepiece.

Who is it for

This telecentric extender is built for advanced amateur astronomers and professional researchers who demand the highest image quality. It is ideal for owners of Baader Solar Spectrum H-alpha filters, astrophotographers capturing the Sun's chromosphere, and anyone performing high-resolution planetary or lunar imaging. If you need consistent magnification without focus shift or edge softness, this lens is for you.

Main features

• 4x magnification factor with fully telecentric design for edge-to-edge sharpness.
• 4-element apochromatic optical system with Phantom Group™ multi-coatings for maximum contrast and minimal stray light.
• Large 46 mm clear aperture and 36 mm fully telecentric image circle, covering most camera sensors.
• Robust M68 x 1 threaded connections (female on telescope side, male on camera/eyepiece side) for a secure, flexure-free setup.
• Diffraction-limited performance with a flat field, ideal for high-resolution solar, planetary, and lunar imaging.
• Anodized aluminum housing for durability and thermal stability.

Specifications

• Magnification Factor: 4x
• Optical Design: 4-element apochromatic
• Telescope Connection: M68 x 1 (female thread)
• Camera/Eyepiece Connection: M68 x 1 (male thread)
• Clear Aperture: 46 mm
• Back Focus Distance: 120 mm
• Telecentricity: Highly telecentric
• Optical Coatings: Phantom Group™ multi-coatings
• Image Circle (fully telecentric): 36 mm
• Internal Filter Thread: M68
• Housing Material: Anodized aluminum
• Optical Quality: Diffraction-limited
• Compatibility: Baader Solar Spectrum H-alpha filters, various cameras and eyepieces via adapters

Tips

For optimal solar H-alpha imaging, pair this telecentric lens with a Baader Solar Spectrum filter and a monochrome camera. Ensure all M68 connections are tightened securely to maintain optical alignment. Use appropriate adapters to connect your specific camera or eyepiece.