Altair Astro 90mm Aperture TRIBAND D-ERF Solar Energy Rejection Filter - H-Alpha CaK CaH (95mm Glass)

Altair Astro 90mm Aperture TRIBAND D-ERF WITH COVER

• Comprehensive Solar Protection: Specifically designed to safeguard your telescope and solar imaging equipment from excessive heat during solar observation with Daystar Hydrogen Alpha Quark or similar filters.
• TRIBAND Pre-Filter: Combines Hydrogen Alpha, Calcium K-Line, and H-Line in one filter, optimizing solar imaging and saving costs on additional filters.
• Specialized Coatings: Blocks Infrared, Ultraviolet light, and unwanted solar emission spectra, transmitting only the desired wavelengths for sharp solar imaging.
• Precise Bandpass Control: Features a 30nm FWHM Bandpass for both Ha and Calcium wavelengths, ensuring excellent contrast and effective blocking. Transmission rates are approximately 95% for Ha and 90% for Calcium peaks.
• Individual Spectrographic Report: Each filter includes a spectrographic test report corresponding to its serial number, guaranteeing quality and performance.
• Versatile Holder Cell: The 120mm D-ERF filter element is secured in a holder cell with a 115mm clear aperture, fitting most 4-4.5" refractors, including Altair's 102mm and 115mm range.
• Durable and Safe Design: The holder cell, made from UV resistant plastic with embedded aluminium flakes, ensures no pressure on the optics, preventing distortion and protecting the filter glass from breakage.
• Essential for Safe Solar Imaging: Must be used alongside a professional Etalon product with built-in blocking filters, such as the Daystar Quark, to prevent serious eye damage.
• Heat Reduction: Reduces about 98% of heat reaching the optics, preventing off-band drift and protecting your equipment.
• Enhanced Imaging Quality: By reflecting heat before it enters the telescope, the D-ERF leads to sharper images without heat haze from air currents inside the telescope tube.
• Equipment and Etalon Protection: Prolongs the life of your equipment and Etalon by reducing the impact of heat and preventing potential fire hazards.
• Ultra Narrow Band Transmission: Allows the use of ultra narrowband Etalons like the Daystar Quark Chromosphere for longer life, thanks to modern coating methods blocking UV and IR light efficiently.
• IMPORTANT SAFETY INFORMATION: An ERF is a pre-filter and should only be used with a proper commercial Etalon with full blocking filters. Never use the ERF alone for solar observation.
• Easy Maintenance: Includes instructions for safely cleaning the D-ERF, ensuring long-term performance and protection of the coatings.