Filtro H-Alpha 7nm ZWO 36mm circolare non montato

The ZWO H-alpha 7nm narrowband filter is designed for astrophotography and focuses on a wavelength of 656nm. It can be used in combination with O-III and S-II filters to produce "Hubble-like" images. By selectively reducing the transmitted wavelengths, this filter eliminates the effects of public lighting and the Moon.

Its FWHM (Full Width at Half Maximum) of 7nm allows for a high contrast ratio against the sky background on celestial objects emitting in H-alpha. It reduces the intensity and number of bright stars in the image field and also enables increasing the contrast of hydrogen nebula extensions.

The aluminum cell is manufactured by CNC machines that ensure high precision fabrication. The filter is available in 4 formats: unmounted 31.7/50.8mm and 31mm/36mm circular.

Technical Specifications

• Transmission on the H-alpha line (656.3nm): 90%
• Bandwidth: FWHM 7nm (+/-0.5)
• Cut-off in infrared (700/1100nm)
• Schott glass
• Glass thickness: 1.85mm
• Precision 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 with CNC machining

Usage

This filter is incompatible for visual observation and silver halide photography. However, it excels at enhancing the contrast of nebulae in CCD imaging, digital photography (modified camera), and webcam/video (deep sky).