No 15 Deep Yellow colour filter to fit 1.25" filter threads (67% transmission). Enhances Martian surface detail and polar ice cap detail. It is effective at enhancing the red and orange cloud belt detail on Jupiter, Saturn and even Venus. Works well to improve contrast on the Moon. Useful for enhancing contrast to make Venus and Mercury stand out against the blue daylight sky. The filter is made of top quality optical glass and is mounted in a black anodised aluminium holder and is supplied in plastic storage case.