Planeoptically Polished and Phantom Group™ Coated

Discover your telescope anew – with the Baader Contrast Booster:

A unique filter for many different astronomical tasks ndash; incomparable in acuity to combinations of generic colour filters, made of raw polished glass – where surface inaccuracy adds up in the optical wave front to an unbearable degree. Especially designed to improve the beginners telescopes – to provide a professional replacement for the simple "dark green" Moon & Solar-Filters made of "raw polished" glass. 

For Solar Observation use only in combination with Baader AstroSolar Safety Film!

Features:

• Eliminates the colour error of economy refractors.
• Clearly puts the real quality of the lens on display.
• Removes the bluish "hue" (=lack of contrast) during lunar-, planetary-, solar- and terrestrial observation.
• Strongly emphasizes surface detail on Jupiter and Mars. If you have never seen the GRS (Great Red Spot) on Jupiter – with this filter you will.
• Over 95 % transmission – provides a bright, brilliant image compared to the usual dark green colour filters, used to bring out detail on Jupiter. Colour recognition will be retained.
• The ultimate in lunar filters. Moon (and Sun) appear much more natural in color (with a slight yellowish tint), compared to the usual low priced dark green Moon-filters, usually offered for beginners telescopes.
• Completely removes distracting false colour and the resulting smeared and washed out image details. You have never ever seen the Moon or the Sun (with AstroSolar Safety Film) so tack sharp in an economy priced telescope.
• Blocks atmospheric "stray light" (skyglow). Sky background turns into pitch black.
• Fits into 1¼" and 2" standard filter threads.
• Planeoptically polished, suitable for being used in front of a binocular viewer, or for a-focal image projection during digital imaging (way in front of the focal plane).
• No deterioration of resolution with magnifications of 200x and more – as with "raw polished" (flame polished) glass.
• Substrate (glass melt) Neodymium doped glass.
• Coating / rear face: 7-layer hard-multicoating, featuring 0.25% reflection.
• Coating / front face: 23-layer dielectric long pass blocker.
• Ionbeam hardened coatings on both faces, absolutely scratch resistant – may be cleaned any time without fear with Baader Optical Wonder Fluid.
• A significant part of city light air pollution, as well as atmospheric Airglow is removed from the telescopic image.

THE TRANSMISSION LINE OF BAADER CONTRAST BOOSTER

The transmission line of Baader Contrast Booster

The transmission line of Baader Contrast Booster, combined with the UV/IR cut filter for CCD Astronomy

The transmission curve shows the light transmittance in percent versus the light wavelength in nanometres. Note the high transmission for visual observations of H-alpha (98%), H-beta (87%) and OIII (82%).

In a light polluted town or city mercury and sodium vapour street lights emit at 435nm and between 570-590nm. Here the filter transmission is between 0.3 and 3%.

Together with the Baader UV / IR cut filter Baader Contrast Booster is additionally an optimal filter for CCD images from light-polluted big city and metropolitan area (see second filter curve).