Baader Filters f/2 Highspeed SII CMOS 1.25" (70921)

The SII filter is a narrowband filter designed for nebula photography. It transmits 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 look of images from the Hubble Space Telescope, such as the famous Pillars of Creation in the Eagle Nebula (Messier 16), the SII filter is an excellent addition to your setup after H-alpha and OIII filters. Like the H-alpha filter, the SII filter is a deep red filter near 672 nm. Using H-alpha, OIII, and SII filters together allows you to create stunning images of many emission nebulae. Additionally, tri-color narrowband imaging with these three filters can be performed even during bright moon phases, ensuring your equipment remains in use.

Specifications

• Central wavelength: 671.7 nm
• Half-value width: 6.5 nm
• Frame size: 1.25 inches
• Mount material: Aluminium
• Coating type: Reflex-Blocker
• Connection to telescope: 1.25 inches
• Appropriate for f-ratio range: f/3.4 - f/1.8
• Filter thickness: 2 mm

General Information

• Type: Filters
• Build type: Line filter
• Series: f/2 Highspeed

Area of Application

• Useful for photographs: Yes
• Visually useful: No
• Twin stars: No
• Moon and planets: No
• Nebulae and galaxies: Yes