Baader Filters Narrowband SII CMOS 1.25" (70865)

The SII filter is a narrowband filter that passes light at a 672 nm wavelength with a bandpass of 3 nm, designed specifically for nebula photography. It is ideal for imaging most emission nebulae, planetary nebulae, and supernova remnants.

If you want to replicate the iconic look of Hubble Space Telescope (HST) images, such as the famous "Pillars of Creation" in the Eagle Nebula (Messier 16), the SII filter is an excellent addition to your collection after H-alpha (H-a) and OIII filters. Like the H-a filter, the SII filter is a deep red filter near 672 nm. Together, H-a, OIII, and SII filters enable tri-color narrowband imaging to achieve that Hubble look for many emission nebulae. These filters also allow imaging even when the moon is up, ensuring your equipment remains productive without long delays.

Specifications

Capacity
Central Wavelength (nm): 671.7
Half-Value Width (nm): 6.5

Frame
Size: 1.25"
Mount Material: Aluminium
Coating: Reflex-Blocker™
Filter Thickness (mm): 2

Connection to Telescope
Size: 1.25"
Aperture Ratio Range: f/10 to f/3.5

General Information
Type: Filters
Build Type: Line filter
Series: Narrowband

Area of Application
Useful for Photographs: Yes
Visually Useful: No
Twin Stars: No
Moon & Planets: No
Nebulae & Galaxies: Yes