Optolong H-Alpha filter 7nm, 2"
The best H-alpha line filter for astrophotography of emission nebulae with the highest contrast and reproduction of the most delicate details of the nebula.
♦ narrow band line filter (<=7nm) for important nebula line
♦ preferred for CDD cameras with full frame transfer technology
♦ 2mm thick and therefore homofocal with many other Optolong filters
♦ Interference filter
♦ Filter holder for 2"
♦ optically polished
♦ Multi-layer hard coating - non-reflective and largely scratch resistant
Optolong H-Alpha filter 7 nm, Filter holder for 2"
The 7nm H-alpha filter is the most popular line filter with a bandwidth of only 7nm and a center wavelength of 656nm. Transmission at the other wavelengths is extremely reduced, particularly those using artificial light sources such as mercury vapor and both types of sodium vapor lamps radiate, but also unwanted natural light emitted by neutral oxygen in the atmosphere. (skyglow).
The best H-alpha line filter for astrophotography with the highest contrast and reproduction of the most delicate details of the nebula.
Main use and properties
♦ Suitable for photographing weak emission nebulae in moonlight or when there is a lot of light pollution
♦ By combining H-alpha, OIII-CCD and SII-CCD, narrowband recordings can be made in the so-called "Hubble palette", such as the famous "Pillars of Creation" (M16, Eagle Nebula).
♦ With the ability to shoot in moonlight and light pollution with line filters, your team won't sit idle for weeks out of the month.
| Substrate: | High-quality optical glass from Schott |
| Thickness: | 2.0 mm |
| Surface Treatment: | Fine-optically polished |
| Surface Polish Quality: | 60/40 (Refer to MIL-O-13830) |
| Surface Quality: | 1/4 wavefront |
| Coating: | Muti-coated |
| Cell: | Unmounted glass plate with 31 mm diameter |
| Typical transmission off-band: | 0.1% (OD3) |
| Centre wavelength H-alpha: | 656.3 nm |
| FWHM H-alpha: | 7 nm |
| Typical transmission H-alpha: | <85% |
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