Baader Semi-APO 1.25 inch Filter

The Baader Semi-APO 1.25" Filter is a high-quality color correction filter designed specifically for achromatic refractors. It effectively reduces chromatic aberration (false color) and enhances contrast, delivering sharper and more natural views of the Moon, planets, and other celestial objects. Manufactured by Baader Planetarium, this filter features advanced Phantom Group™ multi-coatings for maximum light transmission and minimal reflections.

Advantages

This filter significantly improves the visual performance of achromatic refractors by suppressing the violet/blue halo that often surrounds bright objects. It enhances planetary and lunar detail, providing clearer and more contrast-rich images. The multi-element optical design ensures minimal light loss, preserving brightness while correcting color. The included protective case keeps the filter safe when not in use.

Suitable for

• Visual observation with achromatic refractors
• Planetary and lunar observation
• Reducing chromatic aberration in telescopes
• Enhancing contrast and color rendition

Key specifications

• Filter Type: Semi-APO Correction Filter
• Filter Size: 1.25 inches (M28.5 x 0.6 thread)
• Optical Design: Multi-element, color-correcting
• Coatings: Baader Phantom Group™ Multi-Coatings
• Housing Material: Black anodized aluminum
• Glass Material: High-quality optical glass
• Storage Case: Included protective plastic case

Recommendations

For best results, use this filter with achromatic refractors of any aperture. It is also compatible with any 1.25" eyepiece or diagonal. Pair with other Baader filters for a complete observation set.