Baader U-Venus Filter - 350nm

Venus's surface is hidden by a uniform, highly reflective cloud deck in visible light. At 350nm in the deep ultraviolet, specific chemicals in the atmosphere absorb sunlight, creating dark, high-contrast patterns. This allows imagers to capture the dynamic cloud structures and weather systems that are otherwise completely invisible.

You must use a monochrome imaging camera with high sensitivity in the ultraviolet spectrum. Standard color cameras have internal filters that block UV light, and many older mono cameras have low UV quantum efficiency. Modern mono CMOS sensors are generally the best choice for this application.

No. The human eye is not sensitive to the 320-380nm wavelengths passed by this filter. It is designed exclusively for photographic and electronic imaging with UV-sensitive cameras.

While you might record a faint signal, it is not recommended. Successful UV imaging requires significant light-gathering power. Baader recommends a minimum aperture of 5 inches, with 8 inches or more being ideal to achieve a bright enough image for lucky imaging techniques and to overcome the dimness of the UV signal.

By completely blocking all visible and near-infrared light, the filter ensures that only the desired 350nm UV signal reaches the sensor. This prevents longer wavelengths from "leaking" through and washing out the faint UV cloud details, which dramatically increases contrast and reveals subtle atmospheric features.

This is not its intended purpose. While some specialized research involves UV imaging of reflection nebulae or specific star types, the vast majority of deep-sky objects are extremely dim in the UV. This filter is highly optimized for imaging the solar system's brightest inner planet, Venus.