Altair Astro 115mm Aperture Hydrogen Alpha D-ERF (120mm filter with housing cell)

Altair 115mm Aperture Hydrogen Alpha D-ERF Solar Filter

• Advanced Solar Protection: The Altair Dichroic Solar Energy Rejection Filter (D-ERF) is designed to protect telescopes and solar imaging equipment from excessive heat build-up during solar observation and imaging.
• Specialized for Hydrogen Alpha & Calcium K and H: Engineered to transmit desired Hydrogen Alpha, Calcium K-Line, and H-Line wavelengths, perfect for solar imaging with third-party Etalon filters.
• High Heat Reduction: Reduces approximately 95-98% of heat reaching the optics, preventing Etalon drift and protecting the equipment.
• Narrow Bandpass Precision: Features an extra narrow 30nm FHWM Bandpass for Hydrogen Alpha wavelengths, ensuring high contrast and detailed solar imaging.
• High Transmission Rates: Offers 94% transmission at the critical Hydrogen Alpha wavelength of 656.28 nm, maximizing imaging efficiency.
• UVIR Blocking Efficiency: Average OD5 blocking reduces over 98% of unwanted UV and IR heat, further safeguarding your solar observation setup.
• Durable BK7 Glass Construction: Utilizes high-quality BK7 glass with multilayer dichroic coatings and a protective SiO2 super hard overcoat against moisture and scratches.
• Holder Cell Included: Comes with a holder cell made from UV resistant plastic with embedded aluminium flakes, fitting refractors with dew shield diameters of 147mm to 125mm.
• Safety and Compatibility: Must be used in conjunction with a professional Etalon product like Daystar Quark, with full blocking filters for safe observation.
• Comprehensive Heat Management: By reflecting heat before it enters the telescope, the D-ERF contributes to a sharper image, reduced equipment strain, and prolonged product life.
• Special Coating Process: Coatings are applied and baked to release tension, ensuring the filter's longevity and performance.
• Easy Maintenance and Cleaning: Includes recommendations for safe and effective cleaning, maintaining optimal performance without damaging the filter.
• IMPORTANT SAFETY INFORMATION: An essential pre-filter, to be used exclusively with professionally made Solar Etalon Filters, ensuring safe solar observation practices.