A popular filter for the study of Jupiter's disc; owing to the filter's strong rejection of orange and red wavelengths. Increases contrast between the reddish belt structures and enhances detail of the Red Spot. Also useful for the study of isolated phenomena; such as dust storms; on Mars; as well as the belt structure of Saturn. Increases contrast of subtle cloud markings on Venus.
Ed ~ Due to the low light transmission a 4" or larger telescope is required. A bonus feature is that the filter, apart from being a superb planetary filter, can be used as a lunar filter. Owners of smaller aperture telescopes should consider the Wratten #80A or B filters.
