Use this 1.25" Minus Violet Filter, by Lumicon, to enhance your astro-imaging prowess on any lens. Designed using specially made colored glass that is optically flat, the filter features anti-reflection coatings on all optical surfaces. Be sure to use this filter for all telephoto lenses to achieve pinpoint star images.

The Minus Violet filter passes the maximum amount of visible light, including the full blue, green, yellow, and red portions of the spectrum. It absorbs violet and ultraviolet light below 420 nm and thus eliminates blue halos around bright stars in color photography. In photography, it eliminates bloated and swollen star images caused by violet and ultraviolet light, which telephoto lenses cannot focus exactly, due to chromatic aberration.