Antlia Methane CH4 Planetary Filter - 1.25"
Antlia CH4 Methane Filter - 1.25"
Antlia methane (CH4) filter is a specialized filter that allows light in the near infrared portion of the spectrum centered 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 methane, which 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.
Warnings When Using the Methane Filter
Please note that the CH4 filter is not for visual use. For solar imaging use, if an energy rejection filter is not used in conjunction with the Methane Filter, then the heat can be sufficient to damage the telescope, the Methane Filter, and the imaging system.
Technical Specifications:
- Center Wavelength: 889nm
- Filter Thickness: 2mm+/-0.05mm
- Surface Quality: 60/40 (Refer to MIL-O-13830)
- Wavefront: Both sides are fine-optically polished to assure 1/4 wavefront
- Parallelism: 30 arcsec
- Tave>90% transmission at 889nm
- OD5 (>0.001) @ 200 - 1050nm
- Filter Size: 1.25" Mounted (28.5*0.6)