Antlia H-Alpha 2" 4.5 nm EDGE Astrophotographic Filter

The Antlia H-Alpha 2" 4.5 nm EDGE is a premium astrophotographic filter, expertly designed for capturing the distinct red light emitted by ionized hydrogen atoms. Its narrow half-transmittance window width (FWHM) of 4.5 nm makes it exceptionally suited for imaging emission nebulae, where recording the hydrogen alpha (Hα) spectral line is vital.

Key Features

• High Selectivity: Effectively blocks unwanted light from sodium and mercury lamps, ensuring superior transmission of the Hα spectral line.
• Superior Glass Substrate: Built on a high-quality optical substrate to minimize internal reflections, preserving image quality.
• Steep Transmittance Slope: Maintains high transmittance levels without significant decreases, even with shifts in the maximum transmittance peak (CWL).
• Wide Telescope Compatibility: Performs exceptionally well with telescopes across various light intensities, particularly effective with optical systems up to f/3.
• Specialized Use: Not recommended for visual or solar observations due to its specialized nature.

Highlights

Additional Advantages of the Antlia H-Alpha 2" 4.5 nm EDGE Filter:

• Engineered as a bandpass filter with a half bandwidth (FWHM) of 4.5 nm, optimizing transmission at the 656.3 nm wavelength.
• Ideal for use with astrographs with light intensity up to f/3, ensuring minimal signal loss during astrophotography sessions.
• Optical density equivalent of OD5 for effective light pollution reduction.

Technical Specifications

• Filter Type: Bandpass filter
• Filter Diameter: 2"
• Filter Thickness: 2 ± 0.05 mm
• Filter Shape: Round
• Pass Bands: Hα (656.3 nm)
• Peak Transmittance Location (CWL): 656.3 nm
• Half Bandwidth (FWHM): 4.5 nm
• Maximum Transmission: >90% ± 1 nm from the maximum transmission peak
• Blocked Light Pollution Bands: Mercury lamps (435.8 nm, 546.1 nm, 577 nm, 578.1 nm), sodium lamps (589.0 nm, 589.6 nm, 615.4 nm, 616.1 nm)
• Optical Density Equivalent: OD5 (300 - 1000 nm)
• Surface Quality Index: 60/40 (according to MIL-O-13830)
• Parallelism: 30"
• Manufacturing Accuracy (RMS): λ/4
• Holder Thread: M48x0.75

Package Contents

• Antlia H-Alpha 2" 4.5 nm EDGE filter

Warranty Information

The Antlia H-Alpha 2" 4.5 nm EDGE filter is backed by a 3-year manufacturer's warranty, covering any delamination of the filter and substrate.