Baader 1.25" CMOS Optimized LRGB Filter Set

Baader 1.25" CMOS Optimized LRGB Filter Set

Astro-imaging with modern CMOS cameras using Baader 1.25" LRGB Bandpass color filters is achievable for nearly all telescopes independent of optical speed. In fact, these filters are compatible with any telescope that has a focal ratio between f/15 and f/1.8. Notable features include a balanced design, steep slopes at all transmission curves, blackened lens edges with telescope-sided black outer rim around the entire circumference. Highly coveted 1:1:1 subframe exposures, a must for automated imaging, are realized due to this filter's balanced design. Remarkably low levels of stray light and reflections, as well as peak color contrast that matches regular CMOS QE and s/n ratio, are both attainable through steep transmission curve slopes. Finally, unwanted reflections are lessened even further thanks to blackened lens edges with black outer rim on the telescope side that serve as a filter-lead-side-indicator.

Enjoy 98% transmittance for emissions within the visual spectrum (420 nm to 685 nm) along with the simultaneous complete restriction of any UV or IR light on the outskirts of this range with the CMOS optimized Luminance “L” filter from the Baader LRGB filter set. This includes potentially damaging thermal radiation in the infrared. Astrophotographers using red-sensitive digital, CCD, or CMOS cameras will greatly appreciate the sharper star images they are able to obtain thanks to this filter.

The majority of filters available from other manufacturers, especially those of the more moderately priced variety, are cut from a larger glass plate. As a result, they form micro-cracks around all edges that make them vulnerable to depreciation through the moisture accumulation, thus causing premature aging. This is not the case, however, with these 1.25" LRGB filters from Baader. Each individual filter in this set contains scratch-resistant Reflex-Blocker™ hard coatings as well as Life-Coat™ sealed coating edges to insulate them from the external environment. The quality of these filters will not diminish no matter how many times you clean them or how long you own them. Filter thickness matches current standards with particular concern for parfocality.

Baader CMOS Optimized LRGB Filter Set Highlights

• CMOS optimized 1.25" LRGB (Luminance/Red/Green/Blue) Bandpass Filter Set from Baader designed for use with between f/15 and f/1.8 focal ratio telescopes.

• Both stray light and reflections are minimized to a previously unthinkable level via the exceptionally high transmittance of each filter's individual color channel.

• Balanced 1:1:1 subframe exposures, vitally important for performing automated imaging tasks, can be captured by using these filters.

• Transmission curves on all three color filters have steep slopes to increase contrast.

• Separately coated rather than carved out of a larger glass plate, these Baader LRGB filters are all planeoptically polished with Reflex-Blocker™ hard coatings and Life-Coat™ sealed coating edges.

• These parfocal filters meet the current standards for filter thickness.

• The entire circumference contains blackened edges with black outer rim on the telescope side that acts as a filter-lead-side-indicator to prevent reflections resulting from light emissions spilling onto the edge of the filter.

• Luminance "L" filters allow up to 98% transmission of visible light (420 to 685 nm) while completely cutting off any emissions from the UV or IR ends of the spectrum, including dangerous thermal radiation in the infrared.

• Using the "L" filter with red-sensitive digital and CMOS/CCD cameras makes stars seem a lot less blurry.

• Using the "B" and "G" filters together doubles the energy emitted from the O-III line, leading to the utmost peak transmission for the best possible deep sky S/N yield.

• Simultaneously suppress infrared and near infrared emissions from 680 nm up to 1200 nm, while enhancing light from H-Alpha and SII emitting objects with the "R" filter.

• Sources of inconvenient light, such as that from Mercury and Sodium vapor street lamps at 580 nm, are totally neutralized via the use of "G" and "R" filters, resulting in a darker background sky and color balance and separation that is without equal.

• Suitable for use with older CCD cameras despite being designed specifically with modern CMOS technology in mind.

About the Luminance "L" Filter

The obstruction of UV and IR light originating from the extreme non-visible ends of the spectrum is the main purpose of the Baader Luminance "L" Filter. This includes complete blockage of damaging thermal radiation in the infrared, as well as the prevention of blurry stars when working with digital or CCD/CMOS red-sensitive cameras. Meanwhile, all visible spectral areas between 420 nm and 685 nm are allowed to pass at a 98% transmission rate.

About the Red "R" Filter

With the Red "R" Filter, only transmissions from 595 nm to 690 nm wavelengths are permitted to pass, including those of deep sky objects in the H-Alpha line. While there is an intentional overlap between the "G" and "B" filters in terms of spectral emissions allowed to pass, a purposeful gap between the shortest part of the "R" region and the longest part of the "G" region results in the exclusion of a wide range of unwanted light emissions from street lamps and other terrestrial sources. Red "R" filters fully obstruct the NIR and IR from 680 nm up to 1200 nm while keeping maximum transmission of H-Alpha and SII emissions extremely high.

About the Green "G" Filter

Best suited for imaging O-III emission line objects using CMOS monochrome cameras, Green "G" filters transmit wavelengths between 490 nm and 580 nm. Despite the previously mentioned "G" and "B" filter overlap, the crucial H-Beta and O-III emission lines are clearly independent from one another. Although there are no critically important emission lines to be found in the vicinity of 580 nm, Mercury and Sodium vapor street lights do emit from this region. However, thanks to Baader's RGB filter design, these unfavorable emissions are cut off almost entirely, resulting in a darker sky background as well as better color balance and separation.

About the Blue "B" Filter

Of the three Baader RGB filters, The Blue "B" Filter allows the transmittance of the shortest wavelengths (400 nm to 510 nm). This is especially useful for applications involving objects emitting from the H-Beta line (486 nm) such as the Horsehead nebula. Like the "G" filter, the "B" filter also passes O-III emissions (501 nm). When used in combination, these two filters provide double the O-III line energy for unmatched deep sky S/N via extremely high peak transmission.