About this product
Antlia 1.25" Methane CH4 Planetary Filter
Antlia methane (CH4) filter is a specialised filter that allows light in the near infrared portion of the spectrum centred at 889nm to pass through with a bandpass that is 20nm wide. This filter was developed in order to measure finer details and more contrast of the methane that is characteristic of Jupiter, Mars, Saturn and other planets.
The human eye is not sensitive to light beyond about 700nm hence no person can see what is transmitted by this filter, so this filter is not suitable for visual applications.
The Methane (CH4) filter is recommended for planetary imaging such like Mars, Jupiter, Saturn and the other planets.
In order to produce good results, you are likely to require relatively longer exposures times and larger aperture telescope with this filter than with other filters.
IMPORTANT: These filters are NOT designed for observing or photographing the Sun. DO NOT use these filters to observe or photograph the Sun. If you do it will result in permanent eye damage!
- 1.25" Methane (CH4) planetary filter
- 20nm bandpass centred at 889nm
- Ultra-thin filter cell to minimise vignetting and maximise clear aperture
- Not suitable for visual observations
- Helps improve the sharpness when planetary imaging
- Edge blackened to eliminate internal reflections from stray light
- 2mm+/-0.05mm glass thickness
- Fine-optically polished on both sides
Thickness: 1.25” (2mm+/-0.05mm)
Surface Quality: 60/40 (Refer to MIL-O-13830)
2 sides fine-optically polished to ensure accurate 1/4 wavefront
30 arcsec parallelism
Center-Wavelength of Antlia CH4 filter: 889nm
Tave＞90% , 90% transmission at 889nm
2 sides Multi-layers anti-reflection coating
Single / Non-glued substrate
Ultra-thin filter cell to minimize vignetting by maximize possible clear aperture
Black Anodized Finish
Laser Engraving No Fading
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