The hot tip for the 2003 Mars opposition! With the help of these filters, imaging Mars with webcams is possible from all over the world.
The trick: not - in addition to colour exposures, one makes an extra exposure for the 'LUMINANCE' channel, but not, as is usually the case, at the spectral range from400-700nm, but rather deep into the red, staring at 670nm. The transmission window for the deep red starts at 670nm, just barely in the visible range, so that you can properly focus.
The effect: At the long wavelength end of the spectrum, atmospheric air turbulence ('seeing') has a much lower affect on image sharpness! Dark structures on Mars, Jupiter, but also on the Moon and Sun, for example, are significantly sharper and can be incorporated as into a fourth colour image information channel when RGB- imaging. An exciting addition to the 'arsenal' of ideas against bad seeing for every CCD camera owner.