Baader Filters SII CMOS f/2 Ultra-Highspeed 31mm

SII Filter: The narrowband S-II 7nm filter allows light at a 672nm wavelength with a bandpass of 3nm, specifically engineered for nebula photography.

It proves effective for capturing the essence of most emission nebulae, planetary nebulae, and supernova remnants.

If you aim to replicate the captivating aesthetics of Hubble Space Telescope (HST) images, such as the iconic “Pillars of Creation” in the Eagle Nebula (Messier 16), then the SII (es-two) or sulfur filter becomes an essential addition to your kit after H-alpha and OIII. Operating in the deep red spectrum near 672 nm, similar to H-alpha, the SII filter contributes to achieving that signature Hubble-like appearance for many emission nebulae when used in combination with H-alpha and OIII filters. Moreover, performing tri-color narrowband imaging with these three filters remains feasible even under moonlit conditions, ensuring your equipment remains active and productive.

Specifications:

Capacity:

Central Wavelength: 671.7 nm

Half-value Width: 4 nm

Frame: Ring

Mount Material: Aluminum

Coating of Optical System: Reflex-Blocker™

Suitable for apertures ranging from f/3.4 to f/1.8

Filter Thickness: 2 mm

Filter Size: 31 mm

General:

Type: Filters

Type of Build: Line filter

Series: f/2 Ultra-Highspeed

Area of Application:

Useful for Photographs: Yes

Visually Useful: No

Twin Stars: No

Moon & Planets: No

Nebulae & Galaxies: Yes