The trick: In addition to the color image you make an exposure for the "LUMINANCE channel", but not - as usual - with the spectral bandwidth of 400 to 700 nm, but shifted deep into the red - starting at 670 nm. The transmission window starts at deep red 670 nm, i.e. just in the visible range, so that you can focus properly.

The effect: In the long wavelength spectral range, atmospheric air turbulence (the "seeing") has a much smaller effect on the sharpness of the image! Dark structures on Mars, Jupiter, but also for example on the Moon and the Sun are rendered much sharper and can be integrated as fourth image information into the colored (RGB) image. For every owner of a CCD camera a highly interesting extension of the "arsenal" against air turbulence.

The IR-pass filter in deep-sky use
This is also possible, many hobby astronomers also experiment with deep-sky photography to make the interesting information visible in the near IR range. Especially stars in nebulae can be emphasized, because in this region there are hardly any emission lines and the dust blocks less light.

Note:
The human eye is hardly sensitive in this range, so this filter is intended for photographic applications only.