2" O-III Narrowband Filter Beta 2961178 6.5 nm for Astrophotography

The Beta 2" O-III Narrowband Filter with a 6.5 nm bandwidth is designed for astrophotography and visual observation of oxygen-rich nebulae. It selectively transmits the doubly ionized oxygen (O-III) emission lines while reducing continuum and artificial background light. The filter fits standard 2" filter holders and is suitable for use with refractors, reflectors and common CCD/CMOS imaging systems to enhance contrast of faint emission regions.

Advantages

This O-III narrowband filter offers a narrow 6.5 nm full-width at half-maximum to isolate oxygen emission lines, improving signal-to-noise ratio on O-III dominated objects. By attenuating broadband skyglow and light pollution, it increases visual and photographic contrast without altering telescope focus significantly. The 2" mounting format provides mechanical compatibility with many filter wheels and visual adapters.

Suitable for

• Imaging oxygen-rich planetary and emission nebulae
• Visual observation of nebular structure under light-polluted skies
• Use in 2" filter holders, visual backends, and filter wheels for CCD/CMOS cameras

Key specifications

• Filter type: Narrowband O-III
• Clear aperture: 2-inch mounting format
• Bandwidth (FWHM): 6.5 nm
• Designed transmission: centered on O-III emission lines
• Compatibility: telescopes and imaging systems with 2" filter holders

How to use

Install the filter in a 2" filter holder, visual adapter or compatible filter wheel according to the holder’s instructions. For imaging, place the filter in the optical path in front of the camera sensor; for visual use insert it into the diagonal or eyepiece holder. Frame the target nebula and adjust exposure time and gain to account for reduced overall light throughput. When using the filter with color cameras, consider longer exposures or stacking multiple frames to recover faint detail.

Usage recommendations

Align and collimate the telescope before inserting the filter to ensure best image quality. Use the filter in darker parts of the sky for optimal results, and combine with appropriate calibration frames for astrophotography workflows.