iOptron Filters SII 1,25" (87502)

The SII narrowband filter is designed for nebula astrophotography and transmits light centered at a wavelength of 672 nm. With a narrow bandpass, it enhances contrast and isolates sulfur emission, making it well suited for imaging emission nebulae, planetary nebulae, and supernova remnants.

For astrophotographers seeking the classic Hubble Space Telescope–style appearance, such as the iconic “Pillars of Creation” in the Eagle Nebula (Messier 16), the SII filter is a natural addition after H-alpha and OIII filters. Like H-alpha, SII operates in the deep red region of the spectrum near 672 nm. When combined with H-alpha and OIII in tri-color narrowband imaging, it enables the well-known “Hubble palette” and allows imaging even with the Moon present, keeping equipment productive throughout the lunar cycle.

Technical specifications:
Central wavelength: 672 nm
Half-value width (FWHM): 7 nm
Filter size: 1.25 inches
Mount material: Aluminum
Optical coating: Multiple layers
Telescope connection: 1.25 inches

General information:
Type: Filter
Build type: Line filter

Areas of application:
Suitable for astrophotography: Yes
Visually useful: No
Twin stars: No
Moon and planets: No
Nebulae and galaxies: Yes