Antlia SII 3 nm Pro 31 mm Unmounted Narrowband Astrophotography Filter

The Antlia SII 3 nm Pro 31 mm Filter is an advanced, professional-grade tool specifically built for astrophotography. It is expertly designed to capture the precise 671.6 nm wavelength emitted by double ionized sulfur atoms, commonly found in emission nebulae. This filter undergoes meticulous surface quality testing, adhering to stringent military standards, ensuring exceptional performance for astrophotographers.

Key Features

• Ultra-Narrow Bandwidth: Featuring an extremely narrow half-band width of just 3 nm, this filter excels at eliminating unwanted light from sodium and mercury lamps, while maximizing transmission of the SII spectral line crucial for astrophotography.
• Superior Construction: Manufactured on a high-quality Schott substrate, this filter guarantees optimal transmission for radiation at the 671.6 nm wavelength.
• Astrograph Compatibility: Perfect for use with high-intensity astrographs, such as RASA or Hyperstar, with light intensity reaching f/3.
• Light Pollution Reduction: Equipped with an equivalent optical density (OD5), the filter achieves an impressive 99.999% efficiency in blocking light pollution.

Important Usage Notes

Please note that the SII filter is not designed for visual observation and should never be used for solar viewing.

Technical Specifications

• Filter Type: Bandpass filter
• Filter Diameter: 31 mm
• Filter Thickness: 2 ± 0.05 mm
• Filter Shape: Round
• Transmitted Bands: SII (671.6 nm)
• Peak Transmittance (CWL): 671.6 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)
• 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"
• Execution Accuracy (RMS): λ/4

Included in the Set

• Antlia SII 3 nm Pro 31 mm filter

Warranty

The Antlia SII 3 nm Pro 31 mm filter comes with a three-year manufacturer's warranty, covering any issues related to delamination between the filter and substrate.