Baader Planetarium UHC-L 1.25" Ultra-L-Booster Nebula Eyepiece Filter

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 is the successor to the well-proven plane-optical polished Baader UHC-S filter, providing an improved transmission spectrum adapted to modern LED light pollution. It offers a brighter image than many classic Light Pollution Rejection (LPR) filters, making it suitable for both large, fast instruments and smaller telescopes with a 1.25" eyepiece socket.

For photographers, the UHC-L filter serves as a luminance filter, blocking all UV and IR transmission like a UV/IR cut filter. This results in significantly sharper images on refracting telescopes, especially for cameras without a built-in UV/IR-cut filter.

Like all Baader CMOS-optimized filters, the UHC-L filters are plano-optically polished with ultra-hard, sputtered dielectric coatings. They are scratch-resistant and can be cleaned as often as desired. The Baader UHC-L / Ultra-L-Booster Filter offers all the advantages of the CMOS-optimized Baader filters, including increased contrast, reflex-blocker coatings, identical filter thickness for parfocality, blackened edges, individual coating, and a non-aging Life-Coat.