About the Baader Bright Blue 470nm Bandpass Filter Round Mounted...
Baader Planetarium astronomy filters by far supersede the mediocre quality of common "flame polished" color filters. A fine optical polish and 2 mm thick glass allows the Baader Bright Blue Filter to be inserted anywhere into the optical path without introducing astigmatism or other defects. For instance, they can be used in front of a binocular viewer without degrading the image in any way. Substrates are free of striae and plane-parallel polished to within 30 seconds of arc. This eliminates any double images or ghosting due to wedge errors in the glass.
The filter cell features the largest clear aperture of any telescope filter on the market for complete freedom from vignetting at any focal length. The front "crown" incorporates milled notches, which makes handling and threading the Baader Bright Blue Filter an easy operation in the dark. All surfaces are treated with a 7-layer Multi-Coating, featuring a mere 0.25% residual reflection. It is the most elaborate coating ever applied onto amateur color filters, resulting in a filter free of any false reflections under any incident angle of light. Light is the hottest commodity for all planetary observation. Especially during high magnification work, whether you have enough light or not is the deciding factor for the recognition of the subtlest planetary surface detail, much more important than a horde of different filters of mediocre execution.
Less is more: 7-layer MC-coatings on the Baader Bright Blue Filter not only provide a brighter image, they prevent the softening effect of scattered light! Scattered light kills exactly those subtle features in planetary detail that you are longing to see. Painstaking attention to coatings and perfect optical figuring are simple reasons why the image contrast through these premium filters is so rock-solid.
Baader Bright Blue 470nm Bandpass Filter Round Mounted Features...
Baader Bright Blue 470nm Bandpass Filter Round Mounted Specifications...
Filter Type: Bright Blue
Bandpass: 470nm
Format: Round, Mounted
Threaded: Yes
Purpose: Visual and Photographic
Coatings: Multi
Transmission: 70%