This Baader IR-Pass filter reduces the effect of seeing, resulting in a much sharper image. The filter is ideal for imaging and used for the luminosity channel.
The effect of this filter’s use: The normal spectral bandwidth is 400-700nm. This filter starts at 670nm in the deep red, just in the visual range so it can be focused correctly. At this long-wavelength spectral range the atmospheric air turbulence (seeing) has much lower impact on the sharpness. Dark structures on Mars, Jupiter the Moon and the Sun are thereby rendered much sharper. The luminosity can then be combined with RGB creating a very sharp LRGB image - it's a must for planetary imagers.
This brand new filter is supplied in the original, unopened package as shown in the main image.