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9727 EUR
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price without VAT: 7909 EUR
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Artesky ERF 350 mm (SKU: ERF-350 ) is a high-class Energy Rejection Filter designed for mounting in front of the telescope lens in H-alpha solar observation systems. Thanks to its large diameter and reflective properties, it effectively protects the optical system from overheating and eliminates convection phenomena inside the tube, which deteriorate image quality. Unlike absorbing filters, the Artesky ERF filter reflects unwanted radiation without heating up during operation. It is made of optical glass of very high homogeneity, polished to the quality of the lens surface. The dielectric coating is applied on one side, which minimizes mechanical stress and prevents flatness deformation. The filter transmits light in the 60 nm band around the H-alpha line (656.28 nm), effectively cutting off radiation from the 200-1100 nm range. Thanks to the use of the latest optical coating technology, the filter maintains the full resolving power of the entire optical system. Minimizing thermal energy entering the tube not only increases image contrast, but also protects delicate H-alpha system components (e.g. etalon) from thermal damage. Note: The Artesky ERF filter should only be used as a pre-filter in H-alpha solar observation sets. It should be mounted in front of the telescope objective, with the reflective layer facing the Sun (marked with an arrow). Do not use the ERF filter alone for visual observations - it may cause permanent eye damage. Unframed version - if you need a version with a cell, contact the manufacturer or check the offer of filters in a frame. • protects the H-alpha filter from overheating and damage
• eliminates air turbulence inside the tube, improving image sharpness
• reflects unwanted radiation bands (UV, IR, visible light except H-alpha) without absorbing heat
• ensures high light transmission in the H-alpha band – FWHM 60 nm
• made of high-quality optical glass with high uniformity and precisely controlled flatness
• dielectric coatings applied with the utmost care using advanced machines • ERF 350 mm reflective filter (without frame) • optical diameter: 350 mm
• central wavelength: 656.28 nm (H-alpha)
• Transmission bandwidth (FWHM): 60 nm
• H-alpha band transmission: 95%
• reflection range: 200–1100 nm
• cut-off depth: OD4
• surface quality: λ/4, finish 60-40
• edge chipping: <0.2 mm
• glass thickness: 20 mm
• manufacturer: Artesky – Italy
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