Chroma Jovian Methane Filter

This filter isolates the 889nm methane absorption band, which is where methane gas in a planet's atmosphere absorbs light. By blocking other wavelengths, it allows you to see high-altitude cloud features and atmospheric structures on gas giants like Jupiter and Saturn that are otherwise washed out in standard visible light.

This is a 2-inch round filter, so it is designed to fit into standard 2-inch filter wheels or eyepiece holders. If you use 1.25-inch accessories, you will need a 2-inch to 1.25-inch adapter or a filter wheel that accommodates 2-inch filters.

Parfocal means this filter is designed to maintain focus when swapped with other filters in your set, provided your telescope system is f/4.0 or slower. It saves you the time and frustration of having to refocus your camera every time you switch between your luminance and methane filters.

While it is primarily engineered for planetary astrophotography to capture specific atmospheric data, it can be used visually. However, because the human eye is not very sensitive to the 889nm infrared wavelength, the view will be extremely dim and likely not useful for casual observation.

The 18nm Full Width at Half Maximum (FWHM) is a relatively narrow bandpass that effectively isolates the methane absorption line while still allowing enough light through for a bright, high-contrast image. This balance is critical for capturing sharp details without requiring excessively long exposure times.

Yes, it matters significantly. With a transmitted wavefront accuracy better than 0.25 waves/inch, this filter ensures that the light passing through it remains undistorted, which is essential for maintaining the sharp, high-resolution detail required for planetary imaging.