Antlia H-Alpha 3 nm Pro 50 mm Unmounted Narrowband Filter

The Antlia H-alpha 3 nm Pro 50 mm is a professional-grade astrophotographic filter designed specifically for capturing the red light emitted by ionized hydrogen atoms. With a wavelength of 656.3 nm, this filter is particularly crucial when photographing emission nebulae.

What sets this filter apart is its incredibly narrow half-bandwidth of only 3 nm. This feature enables it to effectively eliminate unwanted components from sodium and mercury lamps while ensuring high transmission efficiency for the Hα spectral line. In the field of astrophotography, the Hα spectral line holds immense significance.

Please note that the Hα filter is not recommended for visual observations.

The key features of the Antlia H-alpha 3 nm Pro 50 mm filter are as follows:

It is a bandpass filter created using a high-quality Schott substrate that maximizes transmission for radiation with a wavelength of 656.3 nm.

It is compatible with astrographs that have a light intensity reaching f/3, such as the RASA or Hyperstar.

It offers an incredibly narrow half-width of the transmitted band (FWHM = 3 nm).

It possesses an equivalent optical density of OD5, ensuring a 99.999% efficiency in cutting out light pollution.

Technical Specifications:

• Filter Type: Bandpass Filter
• Filter Diameter: 50 mm
• Filter Thickness: 3 ± 0.05 mm
• Filter Shape: Round
• Transmitted Bands: Hα (656.3 nm)
• Location of Maximum Peak Permeability (CWL): 656.3 nm
• Half Bandwidth (FWHM): 3 nm
• Maximum Transmission: > 88%
• Blocked Bands: Mercury lamps (435.8 nm, 546.1 nm, 577 nm, 578.1 nm), Sodium lamps (598 nm, 589.6 nm, 615.4 nm, 616.1 nm)
• Efficiency in Blocking Light Pollution: > 99.999%
• Equivalent Optical Density for Blocked Lines: OD5 (300 - 1000 nm)
• Surface Quality Index (according to MIL-O-13830 standard): 60/40
• Parallelism: 30"
• Execution Accuracy (RMS): λ/4

Set Components:

• Antlia H-alpha 3 nm Pro 50 mm Filter

Warranty:

The Antlia H-alpha 3 nm Pro 50 mm filter is backed by a 3-year manufacturer's warranty, covering delamination of the filter and substrate.