ZWO Narrowband Filters H-alpha, SII, OIII 7nm - 31mm Circular Unmounted

The ZWO H-alpha, SII, OIII 7nm narrowband filters are designed for astrophotography and allow you to capture "Hubble-like" images. By selectively reducing the transmitted wavelengths, these filters suppress the effects of public lighting and the Moon.

The aluminum cell is manufactured by CNC machines that impose high precision manufacturing. The filter is available in 4 formats, including the unmounted 31mm circular format.

Technical Specifications

• FWHM (Full Width at Half Maximum) : 7nm (+/-0.5)
• Bandpass: 90% on Ha/S-II/O-III lines
• Infrared cutoff (700/1100nm)
• Schott glass
• Glass thickness: 1.85mm
• Precise optical polishing to ensure a precise wavefront at lambda/4 and parallelism <30" of arc on both surfaces
• Double-sided optical coating
• Anti-reflection treatment
• Aluminum cell construction machined under CNC

Usage

These filters are ideal for CCD imaging, digital photography (modified camera) and allow you to enhance the contrast of nebulae.