Baader Filters SII CMOS f/3 Ultra-Highspeed 1.25" (75584)

The SII filter is a narrowband filter designed for astrophotography. It passes light at a wavelength of 672 nm with a bandpass of 3 nm, making it ideal for capturing emission nebulae, planetary nebulae, and supernova remnants.

If you want to achieve the appearance of Hubble Space Telescope (HST) images, such as the famous "Pillars of Creation" in the Eagle Nebula (Messier 16), the SII filter is a great addition to your setup after H-alpha and OIII filters. Like H-alpha, the SII filter is a deep red filter near 672 nm. The combination of H-alpha, OIII, and SII filters allows for tri-color narrowband imaging, creating the iconic "Hubble look." Additionally, these filters enable imaging even during moonlit nights, ensuring your equipment remains in use regardless of lunar conditions.

Specifications:

• Central wavelength (nm): 671.7

• Half-value width (nm): 4

Frame:

• Size: 1.25"

• Mount material: Aluminium

• Coating of optical system: Reflex-Blocker™

Appropriate for:

• Focal ratio range: f/3.4 - f/2.3

• Connection to telescope: 1.25"

• Filter thickness (mm): 2

General Information:

• Type: Filters

• Type of build: Line filter

• Series: f/3 Ultra-Highspeed

Area of Application:

• Useful for photographs: Yes

• Visually useful: No

• Nebulae and galaxies: Yes

• Moon and planets: No