Baader Contrast Booster Filters

Baader Contrast Booster Filters: 1.25" and 2"

Planoptically Polished with Phantom Coating Group (PCG).

A unique filter for many different astronomical tasks. Incomparable in accracy 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 ubiquitous beginners telescopes – to provide a professional replacement for the simple `dark green` Moon and Solar-Filters made of `raw polished` glass.

(Note: for solar observation use only in combination with Baader AstroSolar Safety Film!)

Baader Contrast Booster Filters Main 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 color 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 colour (with a slight yellowish tint, compared to the usual low priced dark green Moon-filters, usually offered for beginners telescopes.
• Completely removes distracting false color and the resulting 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 each and every standard filter thread; Combines with the (planeoptically polished) BAADER Infrared Cut-Filter. In this combination all blue scatter as well as unfocused near infrared light is completely removed – an absolute MUST for digital imaging!
• Planeoptically polished, suitable for being used in front of a binocular viewer, or for afocal image projection during digital imaging (way in front of the focal plane!)
• No deterioration of resolution with magnifications of 200 x 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
• A significant part of City Light Air Pollution, as well as Atmospheric Skyglow is removed from the telescopic image.

Baader Contrast Booster Filters Transmission Line:

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%.

The Baader Contrast Booster with integrated UV / IR cut filter is both an optimal filter for visual observations as well as for CMOS images from light-polluted big city and metropolitan area.