Antlia H-Alpha 3 nm Pro 31 mm Unmounted Narrowband Filter

The Antlia H-alpha 3 nm Pro 31 mm filter is a top-of-the-line astrophotographic filter designed specifically for capturing emission nebulae. Its primary function is to transmit red light with a precise wavelength of 656.3 nm, which is emitted by ionized hydrogen atoms. This filter plays a crucial role in registering this important spectral line for astrophotography purposes.

What sets the Antlia H-alpha 3 nm Pro 31 mm filter apart is its incredibly narrow half-bandwidth of just 3 nm. This unique characteristic allows the filter to effectively eliminate unwanted components from sodium and mercury lamps, while maintaining a high transmission efficiency for the Hα spectral line. In the realm of astrophotography, the Hα line holds significant importance.

It's important to note that the Hα filter is not recommended for visual observations. Its purpose is specifically geared towards astrophotography.

Key Features of the Antlia H-alpha 3 nm Pro 31 mm Filter:

Bandpass Filter: Manufactured on a high-quality Schott substrate, the filter offers maximum transmission for radiation with a wavelength of 656.3 nm.

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

Extremely Narrow Half-Bandwidth: The filter's transmitted band has an impressively narrow full width at half maximum (FWHM) of only 3 nm.

Optical Density and Light Pollution Reduction: With an equivalent optical density of OD5, the filter effectively cuts out light pollution at a remarkable efficiency level of 99.999%.

Technical Specifications:

• Filter Type: Bandpass Filter
• Filter Diameter: 31 mm
• Filter Thickness: 2 ± 0.05 mm
• Filter Shape: Round
• Transmitted Bands: Hα (656.3 nm)
• Peak Permeability Location (CWL): 656.3 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)
• Light Pollution Blocking Efficiency: > 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 arcseconds
• Execution Accuracy (RMS): λ / 4

Included in the Set:

The Antlia H-alpha 3 nm Pro 31 mm filter is the core element of the set.

Warranty:

The manufacturer offers a 3-year warranty that covers any delamination issues concerning the filter and its substrate.