The SHO filter 5nm 2 inch is highly transparent, allowing the emission spectrum of the nebula to collect as much energy as possible by accumulating exposure. There is higher contrast and the level of the nebula is richer and more delicate. (Please note: This filter set is not suitable for telescopes with a focal ratio below F/5.)
1. The H-Alpha 5nm is an extremely narrow emission-line filter that works by allowing a 5nm bandwidth of light, centered on the 656nm wavelength through, and blocking the transmission of contrast-killing light pollution wavelengths. Wavelengths that are responsible for natural light pollution, or skyglow, are drastically reduced, as is artificial light pollution caused by high and low pressure sodium vapor and mercury vapor lights. The result is a high contrast image that reveals the H-alpha line in all its glory
2. The Sulfur II 5nm Extra Narrowband Filter transmits a 5nm bandwidth of light that is centered at 672nm and drastically reduces other transmissions, including wavelengths of light that are responsible for light pollution (both artificial and natural). Like all SVBONY filters that are designated as “CCD”, this SII filter also blocks infrared wavelengths from 700nm to 1100nm so you don't need a separate IR-Cut filter
3. The Oxygen III 5nm Extra Narrowband Filter transmits a 5nm bandwidth of light that is centered at 500nm and drastically reduces other transmissions, including wavelengths of light that are responsible for light pollution (both artificial and natural). Like all SVBONY filters that are designated as “CCD”, this OIII also blocks infrared wavelengths from 700nm to 1100nm so you don't need a separate IR-Cut filter
Specifications
Model | SV227 | SV227 | SV227 |
SKU | W9187DA | W9187DB | W9187DC |
Type | SII Filter | H-Alpha Filter | OIII Filter |
Size | 2-Inch | 2-Inch | 2-Inch |
Wavelength Range | 300-1000nm | 300-1000nm | 300-1000nm |
CWL | 672nm | 656.3nm | 500.7nm |
FWHM | 5nm | 5nm | 5nm |
Peak Transmittance | ≥90% | ≥90% | ≥90% |
Substrate Thickness | 1.85mm | 1.85mm | 1.85mm |
Wavelength Range | 300-1000nm | 300-1000nm | 300-1000nm |
Blocking | ≥OD5 | ≥OD5 | ≥OD5 |
Clear Aperture | 44mm | 44mm | 44mm |
Surface Quality | 60/40 | 60/40 | 60/40 |
Surface Pparallelism | 1/4λ | 1/4λ | 1/4λ |
Parallelism | 30" | 30" | 30" |
Thread | M48x0.75 | M48x0.75 | M48x0.75 |
Single Thread | Yes | Yes | Yes |
Net Weight | 12.5g / 0.44oz/0.027lb | 12.5g / 0.44oz/0.027lb | 12.5g / 0.44oz/0.027lb |