Askar H-Alpha 7 nm 2" Narrowband Astrophotography Filter

The Askar H-Alpha 7 nm 2" Narrowband Astrophotography Filter is expertly crafted for capturing the deep red light emitted by ionized hydrogen atoms at a wavelength of 656.3 nm. This filter is essential for photographing emission nebulae, allowing for precise imaging of this critical spectral line.

Featuring an impressive narrow half-bandwidth of just 7 nm, the Askar H-Alpha filter eliminates unwanted light from sodium and mercury lamps, ensuring high transmission of the Hα spectral line. This line is a key element in astrophotography, offering unparalleled clarity and detail.

Note: The Hα filter is specifically designed for astrophotography and is not intended for visual observation.

Key Features of the Askar H-Alpha 7 nm 2" Filter:

• Bandpass Filter: Optimized to allow maximum transmission for the Hα spectral line at 656.3 nm.
• Narrow Half-Width: With a Full Width at Half Maximum (FWHM) of 7 nm, it provides precise filtration for optimal results.
• OD4 Optical Density: Ensures exceptional light pollution reduction, achieving 99.99% efficiency.

Technical Specifications:

• Filter Type: Bandpass Filter
• Filter Diameter: 2"
• Filter Thickness: 1.85 ± 0.1 mm
• Filter Shape: Round
• Transmitted Bands: Hα (656.3 nm)
• Peak Permeability Location (CWL): 656.3 ± 1 nm
• Half Bandwidth: 7 ± 1 nm
• Maximum Transmission: >90%
• 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: >99.99%
• Equivalent Optical Density for Blocked Lines: OD4 (200 - 1050 nm)
• Surface Quality Index: 60/40
• Parallelism: 30"
• Light Incidence Angle: 0 - 8°
• Frame Finish: Matte Black, Anodized
• Holder Thread: M48x0.75

Included in the Set:

• Askar H-Alpha 7 nm 2" Filter

Warranty:

The Askar H-Alpha 7 nm 2" Filter comes with a 24-month warranty, ensuring reliability and performance for your astrophotography projects.