CXB astro imaging filters exclusively at Farpoint

The introduction of CXB Astro Imaging Filters marks a continuation of a well-established tradition in advanced astronomical optics. Distributed exclusively through Farpoint Astro, these narrowband filters are designed for astrophotographers seeking precision and stability in data acquisition. The CXB filters represent the same engineering lineage as the renowned Astrodon filters, retaining identical materials, manufacturing processes, and optical performance while carrying a new brand name.
Above photo credit: FarpointAstro

Continuation of a trusted design

CXB Astro Imaging Filters include H-alpha, Oxygen III (OIII), and Sulfur II (SII) options, each offering a full width at half maximum (FWHM) of 3 nanometers. These filters are now in full production and available exclusively through the Farpoint Astro online store. Only limited quantities are released at a time, and availability is managed directly through the company’s e-commerce platform.

The rebranding to CXB follows the conclusion of a legal dispute over the former “Astrodon” name. Despite the change in branding, the filters remain identical in both specification and performance. The same team, equipment, and production methods that once produced Astrodon filters are now behind the CXB label, ensuring no deviation in product quality.

Manufacturing and technology background

The CXB filters are produced in the United States using specialized coating technology that allows for precise control over optical layer deposition. This method involves monitoring and adjusting the film growth process in real time to maintain consistent filter characteristics. Each layer in the coating sequence is measured as it is applied, and subsequent layers are recalculated to maintain exact wavelength alignment.

This manufacturing approach is known for producing coatings that are both highly uniform and nearly 100% dense. Unlike older evaporative coatings that can trap moisture and suffer from refractive index drift, the CXB coating process prevents water absorption and maintains consistent optical properties over time. As a result, the filters are resistant to environmental factors that can degrade performance in traditional thin-film optics.

Durability and lifespan

The dense, void-free coatings of the CXB filters make them highly resistant to humidity-related degradation and delamination, a common issue with older filter designs. Because of this structural integrity, CXB filters can be cleaned without risk of damage when handled appropriately. Their hard coatings and compacted design contribute to a projected operational lifespan exceeding 100 years when maintained under normal use conditions.

This focus on longevity ensures that the filters maintain consistent transmission and blocking characteristics throughout their lifetime. For professional observatories, remote imaging setups, and advanced amateur astronomers, stability of performance is a key requirement for reliable calibration and consistent image stacking across observing sessions.

Optical performance and signal-to-noise ratio

A defining characteristic of CXB filters is their high signal-to-noise ratio (SNR). The SNR in an optical filter context refers to the ratio of transmitted light in the target wavelength band to the blocked light outside of it. The higher the ratio, the cleaner and more efficient the data collection.

CXB filters achieve this through a combination of narrow 3nm bandpass widths and exceptionally high optical density in the blocking regions. Their standard out-of-band blocking reaches Optical Density 5 (OD5), corresponding to just 0.001% transmission of unwanted light. In comparison, many competing filters achieve OD2 or roughly 1% leakage. This difference equates to a roughly 99,000-to-1 SNR for CXB filters versus 99-to-1 in less precise designs.

Such performance allows for cleaner, faster data collection. Astronomers can achieve desired exposure levels in less time, with reduced background contamination from light pollution or unwanted spectral lines. This level of precision is particularly advantageous in narrowband astrophotography where faint emissions from nebulae and other deep-sky objects must be isolated from broadband interference.

Photo credit: FarpointAstro

Legacy of precision engineering

The CXB brand’s transition from Astrodon reflects continuity rather than change. The same engineers and production systems that built the reputation of Astrodon filters are responsible for the CXB line. Manufacturing continues under the same specifications, maintaining tight control over substrate quality, coating uniformity, and spectral calibration.

By maintaining this legacy, the CXB filters preserve the reliability that advanced astrophotographers and research institutions have depended on for years. Each filter is individually tested to ensure wavelength accuracy, transmission efficiency, and blocking performance before shipment.

Applications in modern astrophotography

The 3nm narrowband design of the CXB filters makes them suitable for high-resolution imaging of emission nebulae and other targets dominated by discrete spectral lines. The H-alpha filter isolates the 656.3 nm line associated with ionized hydrogen, while the OIII and SII filters isolate the 500.7 nm and 672.4 nm lines respectively. When used in combination, these filters enable the creation of composite false-color images that reveal the structure and distribution of interstellar gases.

These filters are compatible with a wide range of monochrome astronomical cameras and optical setups. They are frequently used by astrophotographers working under both light-polluted and dark-sky conditions to separate desired signals from background interference. Because of their precise spectral control and blocking efficiency, they are particularly effective for imaging faint nebular structures even under challenging environmental conditions.

Exclusive availability and production control

FarpointAstro has stated that for the foreseeable future, CXB filters will be available only through its official online platform. Each production release consists of a limited batch, ensuring careful quality assurance at each step of the manufacturing cycle. Orders placed through the website are fulfilled directly, and inventory updates correspond with production capacity rather than mass distribution.

This exclusivity model allows for direct oversight of customer service, warranty, and performance tracking. It also ensures that customers receive filters directly from the source without third-party handling.

Material and technical transparency

In describing their production process, the engineers behind CXB emphasize transparency about material choices and coating methodologies. The filters are built using export-controlled optical coating technology developed in the United States, a process that reportedly remains unique to domestic production. This approach combines advanced metrology with proprietary deposition control software, ensuring layer uniformity and precision unattainable with older evaporative systems.

Such transparency appeals to both scientific users who require reproducibility and amateur astronomers seeking confidence in long-term equipment reliability.

Purchase the CXB astro imaging filters only at Farpoint

The reintroduction of these filters under the CXB name ensures the continued availability of a proven optical system known for its performance stability and manufacturing precision. Now distributed solely through FarpointAstro, the CXB astro imaging filters preserve the engineering integrity of their predecessors while operating under a new, clearly defined brand identity.

For astrophotographers prioritizing spectral purity, mechanical durability, and consistency over time, the CXB filters represent a direct continuation of one of the most trusted designs in modern astronomical imaging.

Get your CBX astro imaging filter here