Chroma Jovian Methane Filter, 36 mm unmounted

Chroma Methane Band Filter, 36 mm unmounted

The "Jovian Methane" filter is a special filter for Jupiter, Saturn and limited Uranus and Neptune in the near infrared. In addition, it is suitable for reducing the influence of air turbulence for all planets. Daytime observations of planets are also facilitated.

The filter is especifically applicable to the gas planets, but only for use with infrared-sensitive CMOS and possibly CCD cameras. Visual observations are not possible, because the eye is no longer sensitive in this spectral range.

The atmospheres of the gas planets contain a significant amount of methane which absorbs light in a narrow IR range. As this filter only transmit in this range, the planets appear darker. To be more specific: As methane occurs mainly at a certain altitude, structures below it appear dark, while structures above it look bright.

At Jupiter moons as well as storms like the Great Red Spot appear brighter, at Saturn the moons, equatorial region and ring.

Also important, besides the filter:

The requirement for a successful use is a camera which is sensitive for infrared light, like the ASI462MC, but also DSLR cameras where the IR blocking filter was removed without substitution.

As the filter is relatively dark, a larger apperture is recommended, so reflectors have an advantage. That they do not absorb IR radiation and the focus is at the same distance for all wavelengths, belongs also to the positive aspects.