Notice:  As of 7/29/2025 New production is being arranged.  Please monitor our website for upcoming notices of availability dates and the ability to place pre-orders.

CXB (formerly Astrodon) LRGB Gen2 E-Series True-Balance Sets

CXB (formerly Astrodon) LRGB Gen2 E-Series True-Balance Filters have revolutionized CCD imaging. Their popularity is due to their ease-of-use, high optical throughput and great resulting colors for galaxies, star clusters and nebulae. 

E-Series filters are designed to approximately equalize the flux of red-sensitive detectors, including compensation for the solar photon flux. This means that your RGB color combine weights will be approximately 1:1:1 within perhaps 10% for equal length exposures. This can never be perfect, but it does allow you to take one exposure time for all of your RGB data and therefore, only just one corresponding dark exposure time. Again, this saves you precious imaging time and thus, simplifies your imaging.

Vastly Superior Construction: CXB (formerly Astrodon) filters are made using vastly superior coating technology to nearly all other brands.  They are made in the USA using export controlled technology that no other nation posesses. Anyone can design a good filter but it is how they are made that counts!  That special "how they are made" happens only in the USA and is the reason why our filters are so good.

Modern USA Coating technology controls the deposition of thousands of layers in the filter design, measuring and correcting for the errors in real time.  As each layer is deposited,  the partially constructed filter is optically measured and the remaining layers are re-computed to keep the filter performance on target.  This process essentially makes perfect coatings.   No other country has this technology, it is exclusive to the United States. 

In addition to absolutely precise control of layer deposition our technology produces coatings that are nearly 100% compacted with no voids or porosity.   Old style evaoporated coatings absorb water vapor into the coating which changes the over-all index of refaction and the resulting performance of the filter.  As the humidity changes, so does the optical response of the filter.  For narrowband filters this is a disaster.  Our nearly 100% dense filters are immune to this critical flaw. 

Becasuse our filters are impervious to water penetration they will never "delaminate" like the old style construction of most astronomy filters.  They are hard and can be cleaned without fear os destroying them.   Our coatings have an expected lifetime of more than 100 years. 

Signal to noise: The ratio of the light passed by a filters transmission band (desired) to the light passed by the blocking areas (undesirable) is the signal to noise ratio.  The higher the signal to noise, the faster you will accumulate "good data" for your images.  Good filters not only have high transmission values for the in-band portions but they also have high blocking values for the parts of the spectrum we don't want to accumulate.  Not only do our filters have extremely good in-band transmission, they have insanely good out-of-band blocking.  We've measured our competators filters and our blocking is the best on the market.  CXB (formerly Astrodon) filters deliver the highest signal to noise ratio performance on the market.

Our standard out-of-band blocking is Optical Density 5, or only .001% transmission / leakage.  Most of our cempetators struggle to obtain blocking of OD 2, or 1% leakage (we've scanned their filters, we know).  So, ask yourself, would you rather have a system that gives a signal to noise ratio of 99-to-1 or 99,000-to-1?

If you want to make the best images, you need the best tools.  Step up to the best, step up to CXB.

Features:

• Set includes Luminance (NIR/UV-blocked colorless), Red, Green and Blue filters
• 1.25" mounted, 31, 36, 49.7 mm dia, 49.7 mm square (36 mm filters will not exceed 36.1 mm dia.)
• 3 +/-0.025 mm single 1/4-wave fused silica substrate before coating
• 30 arcsec parallelism
• ~1:1:1 color combine weights for G2V white-point for Full-Frame (E) detectors
• Best choice for back-thinned and Sony detectors
• Industry leading in-band transmission
• Industry leading out-of-band blocking
• Equal RGB exposures and one dark time
• Better color separation (see spectra)
• Better color rendition for galaxies based upon color theory
• Significant reflection and star halo reduction
• Enhanced contrast for HII regions in galaxies due to narrower red (not orange) filter
• Spectral "gap" between green and red filters to minimize effect of light pollution, especially from high pressure sodium street lamps (see spectra)
• Highest efficiency blue filter with less UV
• Correct "teal" OIII color for planetary nebula (OIII signal >97% in blue and green)
• Parfocal with CXB's (formerly Astrodon) high-performance narrowband, Clear and Near-IR Luminance filters
• Ultra-hard and durable coatings coated to the edge of each filter
• Proudly made in the U.S.A.

Notice that CXB (formerly Astrodon) filters are coated to the edge. Other filters leave an uncoated "rim" near the edge that must be blocked by a mask or the design of the filter wheel. Our approach minimizes stray light from polluting your image.