Chroma HaLRGB Filter Set The Chroma HaLRGB Filter Set includes five individual filters: 8nm H-alpha, luminance, red, green and blue. They are available in multiple sizes. H-alpha filters are essential for imaging nebulae and other objects which are rich in ionized hydrogen. At 656.3nm, a narrow-band emission filter is required to separate H-alpha from the SII doublet (671.6nm and 673.1nm). Highly precise and accurate, the passbands of these filters remain spectrally stable and do not drift in response to extreme temperature fluctuations or changes in humidity. All filters may be used with apertures of f/4 or smaller. We provide custom coating services for more demanding imaging applications requiring larger apertures such as f/3 or f/2. We also can provide larger sizes and unique passbands upon request. Chroma Technology is an employee-owned company. They specialize in the design and manufacture of sputtered optical filters and coatings for applications that require the greatest precision in color separation, optical quality and signal purity. Their astronomical filters are used worldwide in research and amateur applications. They are as comfortable designing and manufacturing custom filters as they are for their catalog items. We manufacture the highest quality astronomy filters with durable, sputtered hard coatings using single substrates of the best glass, eliminating the need for laminations. All primary filter coatings are applied on the front surface and anti-reflection coatings on the rear surface to prevent ghosting and to maximize transmission. All filters are manufactured in Vermont. Additional features: H-alpha filters are essential for imaging nebulae and other objects which are rich in ionized hydrogen. At 656.3nm, a narrow-band emission filter is required to separate H-alpha from the SII doublet (671.6nm and 673.1nm). Extremely durable coatings withstand humidity changes and extreme temperature fluxes and remain spectrally accuratein CWL and band pass adherence No reflections leading to image distortions or “back reflections” Technical Specifications Durable sputter coatingsParallelism:
