Eyepiece filters are an invaluable aid in lunar and planetary observing. They reduce glare and light scattering, increase contrast through selective filtration, increase definition and resolution, reduce irradiation and lessen eye fatigue.
TPO filters are made of high quality, solid plane parallel glass with excellent homogeneity. They are anti-reflection coated to prevent glaring and ghosting. This eyepiece filter is threaded to fit most 1.25" eyepieces and comes with a hinged, plastic case to keep your filter safe and clean when not in use.
#25 Red (14% transmission): The #25 filter strongly blocks the transmission of blue and blue-green wavelengths, resulting in very sharply defined contrast between, for example, blue-tinted cloud formations on Jupiter and the lighter-toned features of the disc. Also useful for the delineation of the Mars polar ice caps and maria. Because of its relatively low total light transmission, the #25 filter should be employed on telescopes of 8" aperture and larger.
TPO Product Number: OS-F25