Using narrowband filters can often result in slightly dimmer images, which can be difficult to resolve to a focus. You can now use this filter to focus perfectly with a bright image and since they are also parfocal, switch to a different narrow band filter without losing the focus.
This very useful addition to the Baader filter range is intended for the luminance channel in astro imaging. Using narrowband filters can often result in slightly dimmer images, which can be difficult to resolve to a focus.
The ZWO Duo-Band Filter is a dual narrowband filter primarily aimed at complementing our range of colour ASI cameras and offers an economical entry into the world of narrowband imaging and can also offer a practical solution to imaging in light polluted urban areas.
The Optolong extra Narrowband OIII-CCD 6.5nm filter is designed for nebula observation allowing 6.5nm bandwidth of light centered on a wavelength of 500nm through, which corresponds to OIII emission lines, and reducing the transmission of certain wavelengths of light
Optimized light pollution suppression filters for one shot colour CCD and modified DSLR cameras. Not only do these filters block out the majority of the light pollution, they also reduce the red cast improving on the colour balance.