ERF Filter 100mm Artesky (SKU: ERF-100) all astro filters opinie

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Artesky ERF 100 mm (SKU: ERF-100 ) is an Energy Rejection Filter that blocks most of the solar radiation energy from reaching the interior of the telescope. This protects the H-alpha filter from overheating and eliminates thermal turbulence phenomena inside the tube.

The filter mounted at the front of the telescope reflects visible light and radiation outside the H-alpha range. By using high-quality optical glass with a homogeneous structure and a surface accuracy of λ/4, the filter maintains the full resolution of the telescope. It passes only a 60 nm wide band around the wavelength of 656.28 nm, reducing the amount of thermal energy reaching the further elements of the optical system.

Dielectric coatings applied with the highest precision using advanced sputtering machines guarantee perfect flatness and no distortions. The filter is designed exclusively for cooperation with H-alpha filters for solar observations (e.g. Daystar) and cannot be used alone.

Note: The ERF filter should always be mounted in front of the telescope objective, with the coated surface facing the Sun (indicated by the arrow on the filter edge). The product is sold without a mount .

Key Features

• energy rejection filter for solar telescopes
• 60 nm wide transmission band around 656.28 nm
• peak transmission up to 95% in the H-alpha band
• effective reflection of light outside the H-alpha band in the range of 200–1100 nm
• optical glass with high homogeneity and surface accuracy λ/4
• reduction of overheating and turbulence inside the telescope
• only for use in sets with H-alpha filters
• frameless version – for installation in your own cell

Set components

• ERF filter with a diameter of 100 mm (without frame)

Technical parameters

• diameter: 100 mm
• glass thickness: 12 mm
• central wavelength: 656.28 nm
• bandwidth (FWHM): 60 nm
• peak transmission: 95%
• cut-off range: 200–1100 nm
• cut-off depth: OD4
• surface quality: λ/4, finish 60-40
• edge chipping: <0.2 mm