Astronomik CLS Clip-Filter EOS APS-C | EOS APS-C | Standard

Product information "Astronomik CLS Clip-Filter EOS APS-C"

The Astronomik CLS filter is designed for visual observation and photography of nebulae, galaxies, and star clusters using telescopes and lenses. It completely blocks the emission lines from high- and low-pressure sodium (Na)- and mercury (Hg)-vapor lamps, the majority of emissions from LED lamps as well as all lines of natural airglow while allowing the majority of visible light and nebulae emissions to pass through. This enhances the contrast between deep-sky objects and the night sky, making it ideal for photography and observation in light-polluted areas.

Due to its wide passband, the Astronomik CLS filter passes a substantial amount of light, minimally dimming stars. The filter is designed to block as much unwanted light as possible while still transmitting the maximum amount of light from astronomical objects.

Canon_EOS_6D-ohne_Filter_1.jpg?1715850549

Canon_EOS_6D-mit_CLS-Filter_2.jpg?1715850549

20s exposures with JPEG data directly from the camera without further processing. Second image taken with the Astronomik CLS filter. (Canon EOS 6D astro-modified, ISO 6400, Canon EF24-105mm f/4L IS II USM @ 24mm / f/4)

Other uses

The 1.25" and 2" socket models can be used for observations from light-polluted areas.

Alternatives

If there is no built-in IR cut filter in your camera, a Astronomik CLS CCD filter is required.

Suitability of the Astronomik CLS filters

CMOS and CCD photography: Good, requires an additional Astronomik IR-Block filter
DSLR photography (original): Good, color balance is shifted but contrast is enhanced
DSLR photography (astro-modified): Very good, color balance is close to perfect
DSLR photography (MC-modified): Good, requires an additional Astronomik IR-Block filter

Gallery of images taken with our Astronomik CLS CCD filter (using the Astronomik CLS filter with a respective camera will result in identical images)

Difference between Astronomik standard and XT Clip-Filters

The new Astronomik XT-Filters are specifically designed for astrophotography with wide-angle lenses, delivering sharp and crisp star images all the way to the edges of the image. When using very short focal length lenses to take widefield images, standard Clip-Filters could introduce aberrations, stretching stars in the outermost corners of the image. To solve this issue, the new Astronomik XT-Filters are coated on an extremely thin substrate of only 0.3mm or 0,5mm thickness, significantly reducing these aberrations. Despite the reduced thickness, the Astronomik XT-Filters maintain the highest optical quality. They are manufactured using the same durable coating technology as all Astronomik filters. More information about our XT-Filters can be found here.

Technical Data

92% transmission at 486nm (H-beta)
92% transmission at 496nm (OIII)
92% transmission at 501nm (OIII)
97% transmission at 656nm (H-alpha)
Transmission range: 450 to 540nm and above 650nm
Glass thickness: 1mm (except Astronomik OWB Type 3 and XT filters)
Finely polished optical glass, free of any striae, residual stresses, and bubbles
Extremely scratch-resistant and durable coating
Completely resistant against high humidity and aging effects
Astronomik MFR coating (Astronomik Deep-Sky RGB, UV-IR Block L-1, L-2, L-3, and Narrowband-Emissionline filters)
Parfocal with other Astronomik filters
Diffraction-limited
Optimized spectral windows
Delivered in a high-quality, long-lasting filter box

Due to the high-precision machining of the carrier substrate, all Astronomik filters are parfocal with wedge errors far below all common tolerances. Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Issues concerning focal distances and the exact alignment of images from each color channel are therefore effectively eliminated.

All Astronomik filters are ideal for modern cameras, including both CMOS- and CCD-based models, ensuring you capture the best possible images with your equipment. Sharpness, contrast, and the absence of any reflections and halos are guaranteed. Even with bright stars in the field of view, nebulae and galaxies will be captured with the finest structures. The Astronomik MFR coating is designed for optimal performance across a wide range of focal ratios of the optics used.

Every Astronomik filter undergoes a rigorous quality control process before delivery. Additionally, each Astronomik Narrowband-Emissionline filter is measured using a high-end PerkinElmer Spectrophotometer to ensure it meets the specifications published on our website. On the back of each Narrowband-Emissionline filter box, you will find a label detailing the precise spectral data for that specific filter, including the maximum transmission and the recommended range of focal ratios.