Antlia 4.5nm EDGE Filters (H-alpha, SII, OIII)

Overview

Antlia 4.5nm EDGE Filters are engineered to overcome the challenges of conventional narrowband filters, which often experience significant transmission loss due to Central Wavelength (CWL) shifts. With a guaranteed transmission rate of over 90% (T>90%) within a 1nm range of the central bandwidth, Antlia 4.5nm EDGE Filters deliver outstanding performance for both long focal ratios and fast optical systems. Blue-shift analysis confirms their suitability for systems as fast as f/3, minimising signal loss and optimising imaging quality.

Applications and Performance

• Antlia 4.5nm EDGE Filters provide high transmittance and narrow bandwidth to maximise contrast in astrophotography.
• These filters feature a steep spectral profile to minimise halos around bright stars, ensuring clean and precise images.
• Constructed with a single optical-grade substrate, Antlia 4.5nm EDGE Filters eliminate internal reflections for enhanced reliability.
• Designed for imaging deep-sky objects emitting H-alpha, SII, and OIII wavelengths, such as emission nebulae, planetary nebulae, and supernova remnants.
• Antlia 4.5nm EDGE Filters excel in both light-polluted and dark-sky environments.
• Extend imaging opportunities with Antlia 4.5nm EDGE Filters, even under moonlit skies.
• Optimised for optical systems as fast as f/3, these filters minimise signal loss while maintaining superior image quality.

Note: These filters are designed specifically for astrophotography and are effective for capturing H-alpha, SII, or OIII emissions.

Technical Specifications

• Substrate: Optical-grade, single/non-glued substrate.
• Filter Thickness:
  • 2mm ± 0.05mm for 1.25”, 2” mounted, Dia31mm, and Dia36mm unmounted filters.
  • 3mm ± 0.05mm for Dia50mm unmounted filters.
• FWHM (Full Width at Half Maximum): 4.5nm.
• CWL (Central Wavelength):
  • H-alpha: 656.3nm.
  • SII: 672.4nm.
  • OIII: 500.7nm.
• Peak Transmission: >90%.
• Blocking: > 5 OD (out-of-band blocking) @ 300–1000nm.
• Surface Quality: S/D (scratch/dig) = 60/40 (per MIL-O-13830 standards).
• Transmitted Wavefront: Lambda/4 or better.
• Parallelism: Less than 30 arcsec.

Filter Cell

• Sizes:
  • Mounted: 1.25” (M28.5x0.6), 2” (M48x0.75).
  • Unmounted: Dia31mm, Dia36mm, Dia50mm.
• Ultra-thin filter cell to minimise vignetting.
• Black anodised finish with non-fading laser engraving.

Important Notes

• Not recommended for solar observing or visual observation.
• Warranty: 3 years against delamination.
• Warning: Do not look at the Sun with Antlia 4.5nm EDGE Filters. Serious eye damage will result.

Manufacturer's Note

Antlia 4.5nm EDGE Filters are meticulously designed to deliver high-performance astrophotography results. Each filter undergoes rigorous quality control to ensure high transmittance, precise band-pass parameters, and exceptional optical reliability. While halos around bright stars are rare due to advanced engineering, minor halos may occur with certain optical setups. Higher-end filters, such as Astrodon or Chroma, can guarantee halo-free images, but Antlia 4.5nm EDGE Filters provide an exceptional price-to-performance ratio, making them an excellent choice for most users.

Return Policy: Returns are not accepted for halo-related issues.