The H-Alpha 1.25" 12nm filter from Explore Scientific is an essential tool for astrophotographers looking to capture emission nebulae, even under light-polluted skies. This filter blocks almost all other colors, allowing only the emission line of red hydrogen to pass through. It effectively eliminates disruptive light from mercury and sodium vapor lamps, revealing details invisible to the naked eye. With a bandwidth of 12nm, this filter enhances the contrast and sharpness of deep-sky objects, enabling the photography of nebulae that appear invisible without a filter. Ideal for urban astrophotographers, it guarantees surprisingly high-quality results despite light pollution. Each filter comes with an individual test certificate to ensure its high quality.