The Baader UHC-L 1.25" Ultra-L-Booster Nebula Eyepiece Filter is a versatile tool designed for both visual and photographic observation of emission nebulae, including star-forming regions, planetary nebulae, and supernova remnants. This filter is particularly effective under medium to highly polluted skies, making it an essential accessory for urban astronomers and photographers. Engineered with the latest CMOS-optimized coating technology, the UHC-L filter effectively blocks false light more than any previous UHC filters. It also features a unique light pollution rejection capability, blocking the main LED emissions in the blue part of the spectrum. This makes it an ideal luminance filter for LRGB imaging, enhancing the contrast and sharpness of your celestial images.The UHC-L filter's passband curve corresponds to a wide dual-band filter, transmitting all light emitted by known gas nebulae without distorting star colors. It allows the H-alpha and H-beta lines of fluorescent hydrogen and the OIII line of oxygen to pass through, while significantly reducing the atmospheric stray light from LED lamps, car headlights, street lamps, and the natural night sky glow.This filter is also beneficial for comet observation as it allows the OIII line at 501nm and the two C2 lines at 511nm and 514nm, characteristic of many comet gas tails, to pass through. It's the perfect visual complement to narrowband OIII filters for deep-sky observers.The UHC-L filter