The Antlia H-alpha Prime 7nm narrowband filter is designed to deliver high contrast and excellent signal-to-noise ratio (SNR) by optimizing the FWHM (full width at half maximum) to a 7nm bandpass. It incorporates the same high-quality optical coatings found in the Antlia 3nm Pro series, ensuring precise performance and effective suppression of unwanted wavelengths.

This filter achieves 90% transmission at the H-alpha line’s central wavelength of 656.3nm, providing strong signal strength and well-defined nebular structures. Its 7nm bandwidth is also wide enough to effectively capture the nearby nitrogen (NII) emission lines at 654.8nm and 658.3nm, which adds depth and detail to emission nebulae.

With an out-of-band blocking specification rated at OD4 (0.01%), the filter minimizes interference from other wavelengths, improving image clarity. Its steep cut-off profile helps reduce halos around bright stars, resulting in cleaner, more accurate images. The Antlia H-alpha 7nm Prime filter is compatible with most optical systems and performs reliably even with fast setups down to f/2, maintaining strong emission signal with minimal loss.

Application and Performance:

• 90% transmittance at the central wavelength of H-alpha (656.3nm)

• Passes key emission lines including NII (654.8nm, 658.3nm) and H-alpha (656.3nm)

• 7nm FWHM is wide enough to transmit both H-alpha and adjacent NII lines

• Suitable for fast optical systems down to f/2 with minimal signal loss

• Steep spectral curve helps reduce halos around bright stars

• Constructed with a single substrate to avoid internal reflections

• Ideal for capturing H-alpha and NII emission nebulae, planetary nebulae, Wolf-Rayet regions, and supernova remnants

• Effective for imaging in both dark skies and light-polluted areas

• Edge-blackened to block stray light and minimize internal reflections

• High optical quality minimizes the need for post-processing

• Designed for deep-sky targets that emit strongly in H-alpha and NII wavelengths

Not recommended for:

• Solar imaging

• Visual observation at night