Baader's new LRGB anti-reflection filters convey enhanced color separation and picture quality. Sadly, their obvious improvements will probably many astrophotographers to re-take pictures of their favorite objects...
What makes the Baader filters so unique? Through a broad covering stack design and testing program, Baader has bonded together with the world's leading thin film coating manufacturer to create transmission curves that border on the ideal. Their ultra steep cutoffs and high transmission (>95%) permitted Baader to accomplish something to a degree no other RGB filter set can do - they can successfully isolate the vital H-Beta and O-III lines. The Baader Blue filter passes virtually all of the H-Beta and O-III lines, while the Green filter can catch all of the O-III line, without infringing into the H-Beta line. None of the light is wasted by either filter. Along these lines, O-III is represented as it ought to be, a teal (blue-green) color, and H-Beta is captured solely in the blue. Never before has this degree of separation been achieved, and with such high transmission of both lines.
Moreover, the Green and Red filter passbands nearly touch, leaving only a sharp notch to block out the primary Mercury/Sodium light pollution line at 580nm. The high transmission everywhere else delivers the shortest combined exposures possible.
Adding to their unique transmission properties, the Baader coatings were produced considering another key objective - get rid of the irritating reflections present in other astro-filters. To accomplish this freedom from reflections required watchful balancing of the coating stacks and further extensive testing.
The high optical quality of the Baader narrowband filters ensures no loss in sharpness or contrast. Each substrate is fine-optically polished plane parallel to deliver a smooth and exact 1/4 wavefront over the whole surface. Every filter is blocked and individually polished, not removed from a bigger plate of glass. The special custom polishing operation sets Baader filters apart from the lower optical quality provided by standard commercially precision polished filter substrates used by most other filter manufacturers.
Coatings are professionally applied in Germany by the most sophisticated equipment available today, ensuring high consistency for bandpass cutoffs, transmission, and out of band blocking. The anti-reflection coatings are equally balanced on both sides of the filters to reduce surface stresses and prevent the substrates from being deformed. The ultra-hard ionbeam deposition guarantees the coatings will never degrade from use or ordinary cleaning. Unlike competitive filters, Baader coats every filter individually. Baader filters stay sealed at their coating edges for a long life without degradation (you can see evidence of this process by inspecting for a thin un-coated region at the very edge of the filter). Though more costly, this process avoids the coating failures that can result when filters are simply 'biscuit cut' from bulk coated sheet glass, leaving ragged coating edges for moisture to penetrate and cause coatings to peel away from the glass. Baader filters are intended for a lifetime of real-world use.
|Name||Baader Planetarium - 1.25" LRGB Filters - UV/IR Cut L-Filter|
|Manufacturer Part No||FLRGB-1|