Astronomik UHC-E 2" filter (Astronomik, SKU: 10209200) is a filter for observing and imaging emission nebulae and comets. It reduces selected components of light pollution while using a wider passband than the standard UHC, so stars are dimmed less.
UHC-E is particularly useful in smaller telescopes where preserving image brightness matters. The manufacturer recommends it as an option for instruments with apertures up to about 125 mm under light-polluted skies. When imaging with a camera that lacks a built-in IR blocker, separate infrared cut-off is required.
The filter has a 2" cell with an M48 × 0.75 thread. It fits accessories with a matching filter socket; the nominal cell size is not the diameter of the clear glass aperture.
• wider passband and less stellar dimming than the standard UHC
• useful for emission nebulae and comets
• suppression of selected artificial lighting emission lines
• durable coatings resistant to scratching and moisture
• filter: Astronomik UHC-E 2" filter
• protective filter box
• manufacturer: Astronomik
• manufacturer product code: 10209200
• transmission bands: 465–530 nm and above 645 nm
• main passband full width at half maximum (FWHM): 45 nm
• typical transmission: 94% at 486 nm and 656 nm; 95% at 496 nm and 501 nm
• infrared blocking: none
• cell size: 2"
• thread: M48 × 0.75
• glass thickness: 1 mm
• material: finely polished optical glass
• optical quality: diffraction-limited
• coating resistance: to scratching, moisture and ageing
• parfocality: with standard Astronomik filters using 1 mm glass
UHC-E improves the contrast of selected objects without darkening the field as strongly as narrower nebula filters.
