Baader Planetarium Bright Blue 470nm Bandpass Filter for 1.25" Occulars

What sets the Baader Planetarium Bright Blue 470 nm Bandpass Filter apart is its precision-engineered design, specifically tailored for 1.25" oculars. This high-quality filter operates at a bandpass of 470 nm, making it an ideal choice for those seeking to observe celestial bodies in the blue spectrum.

The filter boasts a fine optical polish and 2 mm thick glass, ensuring it can be seamlessly integrated into any optical path without introducing astigmatism or other optical defects. This makes it perfectly suitable for use in front of a binocular viewer, without compromising the image quality in any way.

The substrate of this durable filter is free from striae and is plane-parallel polished to within 30 seconds of arc. This meticulous attention to detail eliminates any potential double images or ghosting caused by wedge errors in the glass.

One of the standout features of this filter is its cell, which offers the largest clear aperture of any telescope filter available on the market. This ensures complete freedom from vignetting at any focal length. The front "crown" of the filter incorporates milled notches, simplifying handling and threading operations, even in low-light conditions.

All surfaces of this effective filter are treated with a 7-layer Multi-Coating, resulting in a mere 0.25% residual reflection. This is the most elaborate coating ever applied onto amateur color filters, ensuring a filter free of any false reflections, regardless of the incident angle of light.

Light is a crucial factor in all planetary observation, particularly during high magnification work. The 7-layer MC-coatings not only provide a brighter image but also prevent the softening effect of scattered light. This is particularly important as scattered light can obscure the subtle features in planetary detail that observers seek to view.

The Baader Planetarium Bright Blue 470 nm Bandpass Filter's commitment to perfect optical figuring and meticulous coating application are the reasons why it delivers such solid image contrast. This is a testament to its high-quality and effective performance in enhancing your celestial viewing experience.