Nebula Filter S-II 1.25-inch 12nm

The Explore Scientific S-II filter passes only the emission line of ionized sulfur at 672 nm, in a 12 nm passband, and absorbs almost all artificial light. It is an astrophotography filter. With a camera, it records the sulfur emission of emission nebulae, planetary nebulae and supernova remnants, including under skies brightened by city lights.

Key Features

• Ionized sulfur line at 672 nm. Passes the S-II emission line and absorbs the other emission lines.
• 12 nm passband. Absorbs almost all artificial light.
• Size. 1.25-inch.
• Individual test report. Each filter ships with its own test report.
• For the camera, not the eyepiece. Ionized sulfur glows at 672 nm, in the deep red, where the dark-adapted eye is about 1/8,000 as sensitive as at its peak. Through an eyepiece this filter shows little or nothing. It is the sulfur channel in narrowband imaging.

Ideal For

• Narrowband imagers recording the sulfur channel of emission nebulae, planetary nebulae and supernova remnants.
• Imagers under skies brightened by city lights, since the filter absorbs almost all artificial light.

Accessories & Compatibility

Explore Scientific also makes this 1.25-inch filter with a 6.5 nm passband (S-II 1.25-inch 6.5nm), which passes a band about half as wide, so less light from outside the sulfur line reaches the camera.