6.5nm SII Narrow Band Filter

This filter is a 6.5 nm SII filter designed for observing nebulae with a wavelength centered at 672 nm and reduces the transmission of certain wavelengths of light, especially those produced by artificial lights , including mercury vapor, high and low pressure sodium vapor lamps and unwanted sodium vapor lamps. natural light caused by the emission of neutral oxygen into our atmosphere (eg Skyglow).

Main use and performance

Narrowband imaging can be obtained by combining the filters of the SHO set (H-ALPHA, OIII, SII), in lunar and light pollution conditions, in this way the equipment does not remain stationary for weeks .

The SII filter does not eliminate the effects of light pollution and does not increase the brightness of the photographed object, but on the contrary increases the contrast between the nebula and the night sky, which facilitates image processing.

This 6.5nm narrowband SII filter is designed for use in filter wheels, in filter holder drawers or directly on the camera (not valid for those not mounted in the cell)
Technical characteristics

Technical data

• Schott Substrate Materials
• Thickness 2.0mm
• Surface quality: 60/40
• Fine optical polishing to ensure accurate 1/4 wavefront and <30 seconds parallelism on both surfaces
• SII filter has 80% transmission, SII line is 672nm
• Precision out-of-band blocking