Developed for CCD astrophotography with your telescope, the OVL filter set contains a luminance IR, red, green and blue dichroic CCD filter. The filters are moisture and scratch resistant and come with a sturdy aluminum frame with filter thread. The red, green, and blue filters are designed to closely match the natural colors of stars, planets, and emission nebulae, while the luminance filter blocks interfering haze and ultraviolet radiation. The filters have a light transmission of almost 100%. Please note that the red, green and blue filters do not have an IR coating. Scope of delivery: 4 filter set storage box! Power supply and batteries are not included!