Alpine Astronomical 120mm Baader AstroSolar BDSF 3.8 White-Light Digital Solar Filter for Telescopes

Unlike many white-light solar filters that produce views of the sun with a red-orange, bluish, or yellow tint, the Alpine Astronomical 120mm Baader AstroSolar BDSF 3.8 White-Light Digital Solar Filter reveals the sun in its natural white color. With an optical density of 3.8, this iteration is specifically designed for digital imaging of the sun and all phases of a solar eclipse through an optic like a telescope or extreme telephoto lenses — showing more surface details with greater clarity versus other types of solar filters. The filter is mounted onto a clear-white IR-rejecting plastic ring, which acts as stabilizing element for the filter cell, and the ring is in turn mounted onto the aluminum front frame. The thermal expansion coefficient of the plastic and the film are similar to minimize thermal stress on the film for increased resistance to developing pinholes or tears. With the ability to be installed on the outside or inside of an optical tube assembly, dew shield, or corrector plate retaining rin...