Lumicon 2" Minus Violet Filter – Reduces Chromatic AberrationThe Lumicon 2" Minus Violet Filter is primarily used to bracket the color corrected band of refracting telescopes by blocking violet and ultraviolet light below approximately 420nm. This helps reduce blue halos around bright stars and minimizes chromatic aberration (purple fringing) in photographs, especially when used with achromatic refractors or telephoto lenses. It can also serve as a visible light filter in RGB astrophotography setups. Most