Color filters can be very useful for enhancing your views of the Moon and the planets. Depending on the atmospheric conditions, the telescope being used, the observer's experience, and the planet being observed or photographed, the advantages of color filters can be anywhere from subtle to dramatic. The right filter can make all the difference between seeing several small craters in the floor of Clavius on the Moon or not; seeing five or six swirls in Jupiter's belts or not; or seeing the inner Crepe Ring of Saturn or not.
Agena's 2" color/planetary filters are manufactured from the purest optical glass and are dyed-in-the-mass (not simply "color coated") for premium performance. They thread into the barrels of virtually any 2" telescope eyepiece. Each filter cell has a male and female 2" filter thread (M48x0.75) on opposite sides, so multiple filters can be stacked to achieve selective filtration of the visual color spectrum. The clear aperture is 43mm and each filter comes in a protective plastic storage case.
The #8 Light Yellow Filter enhances detail of red and orange-colored phenomena in the belts of Jupiter. It increases contrast of the blue-colored Maria on Mars by reducing scattered light from these areas, while allowing passage of more green light thus highlighting yellow dust clouds as well. It provides improved resolution of detail on Uranus and Neptune in large telescopes (over 10"). The light yellow filter is popularly used to enhance lunar features, particularly in small telescopes (below 8"). In comets, it brings out highlights in yellowish dust tails and enhances the coma.
Agena Informational Article: Choosing a Color / Planetary Filter