Antlia Solar Discover Dualband ERF filter (energy rejection)

Antlia Solar Discover Dualband Energy Rejection Filter (ERF)

The Antlia Solar Discover Dualband ERF filter is designed to protect solar imaging equipment by significantly rejecting heat before it enters the telescope. It allows for the targeted transmission of H-alpha wavelengths (656.3 nm), Calcium K-line (393.3 nm), and Calcium H-line (396.8 nm), while effectively blocking ultraviolet (UV) and infrared (IR) radiation.

Key features

• Wide bandwidth of 25nm for H-alpha and CaK/CaH
• High transmission: over 90%
• Advanced multilayer coatings applied to a polished, heat-resistant double-sided substrate
• Coating range extended from 200nm to 1700nm
• Optical quality: Transmitted wavefront λ/4 or better
• Available in several sizes to fit different opening diameters

Applications and Performance

• Thermal protection for solar imaging with Antlia Solar Discover 3nm CaK, 5Å CaK, and Dualband Ha, CaK, CaH Assembly filters.
• Improves equipment safety and reduces heat-induced band offset
• Compatible with refractors ≤110 mm for the 2″ mount version

Technical Specifications

• FWHM: 25nm (H-alpha and CaK/CaH)
• CWL (Center Wavelength):
  • H-alpha: 656.3nm
  • CaK: 393.3nm (covering CaK 393.3nm and CaH 396.8nm)
• Maximum transmission: >90%
• Thickness :
  • 10mm ± 0.05mm for 130mm, 150mm, 200mm mounted
  • 3 mm ± 0.05 mm for a 2″ mounted unit
• Coating Range: 200-1700nm

Available sizes

• 2″ mounted
• ERF 130mm with cell
• ERF 150mm with cell
• ERF 200mm with cell

Important notes

• The Dualband ERF filter cannot be used on its own.
• It must be combined with professional solar equipment that has its own built-in blocking filter.
• Do not use for direct visual observation without a complete solar safety system.
• The 2″ version should be used exclusively on refractors with an aperture of 110 mm or less.

Warranty

• Warranty period: 3 years