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 #82A Light Blue Filter enhances areas of low contrast while avoiding reduction of the overall brightness at the same time. It thus rivals the #80A Blue in popularity, being useful on the Moon, Mars, Jupiter, and Saturn. On the Moon it brings out surface detail; on Mars it is very useful during the violet clearing for studying the polar caps and the surface, while on Jupiter and Saturn it emphasizes the transitions between the various belts. Its use on Mercury and Venus gives results similar to #80A.
It has even been reported useful for bright galaxies, particularly face-on spirals such as the M51. The galactic structure, such as detail in the spiral arms, is more pronounced with the filter. Also, try this one to split binaries. It also enables viewing of cometary gas tails. The light blue filter is also a useful filter to stack along with other filters.