The Baader Solar Continuum Filter 2" is designed to enhance the visibility of solar granulation and sunspot details. By transmitting a specific spectral region around 540nm, free of emission and absorption lines, the Solar Continuum filter is able to boost contrast and reduce the effects of atmospheric turbulence. With the Solar Continuum filter in place, images snap to focus and granulation becomes regularly visible. Details at the limit of visibility become easier to hold and image motion reduced.
The Solar Continuum filter works well in all types of telescopes, for both visual and imaging. Users of SCTs and achromatic refractors will find it particularly beneficial, as it completely excludes the red and blue wavelengths and centers on the peak visual wavelengths where the telescope optics are sharpest and free from chromatic aberrations. For digital imaging, Baader also recommends the Continuum filter be combined with UV/IR Cut Filter (to completely cut the defocused far infrared wavelengths).
The Solar Continuum filter also makes the perfect star test filter. Its narrow bandpass and complete blockage of longer and shorter wavelengths make it superior to standard green colored filters for testing refractors at their center design wavelength (and peak visual wavelength). With this filter, more accurate appraisals of optical quality can be made, without the effects of spherochromatism or secondary color error. Due to the narrow 10-nm bandpass, star testing through the Solar Continuum filter will require a bright test star.