Astronomik CLS Filter The Astronomik CLS Filter is a budget filter for visual observation, Black & White photography and CCD photographs of nebulae, galaxies and star clusters with astronomical instruments of any size. The Astronomik CLS Filter blocks the light of the spectral lines of mercury and sodium-vapor lamps and lets the largest part of the visible light and H-alpha emissions pass. All the important emission lines, as well as the spectral region that the very well dark adapted eye can see, can pass through the filter. Main use The filters are optimized for use with aperture ratios from 1:3 to 1:15. Transmission losses and chromatic distortions, which are problems with other filters, only appear with Astronomik filters when extremely bright aperture ratios of 1:2 and more are used. The CLS filter is suitable for use with telescopes of all aperture sizes. Suitability Visual observation (dark skies): Good, to reduce light pollution by mercury-vapour lamps (streetlight) Visual observation (urban skies): Good, an UHC-E or UHC filter is more suitable Film photography: Very good, colour balance is near perfect CCD photography: Good, when used with an additional IR-block-filter DSLR photography (original): Good, colour balance shifted but contrast enhanced DSLR photography (astro modified): Very good, colour balance is near perfect DSLR photography (MC modified): Good, when used with an additional IR-block-filter Webcam / Video (Planets): Unsuitable Webcam / Video (Deep Sky): Very good, if light pollution is a big problem The table gives you a short Overview about the suitability of our filters for various applications: Legend ++ The filter is excellent for this application, the dramatic better image! + The filter is good for this application, the much better image! o The filter is suitable for this application, the slightly better image! - The filter is usable for this application. -- The filter is not suitable for this application. How to Read the Chart The horizontal axis is the Wavelength in Nanometers (nm). 400nm is deep blue, at 520nm the human eye senses green and at 600nm red. At 656nm is the famous "H-Alpha" emission line of hydrogen. The transmission in % is plotted on the vertical axis. The red line shows the transmission of the filter. Visual filters: The grey line in the background shows the relative sensitivity of the human eye at night. The maximum is at ~510nm and drops to longer and shorter wavelengths. You can easily see, that you can´t see anything of the H-alpha line at night (even if you can during daylight!) The sensitivity at 656nm is 0% at night! Photographic filters: The grey line in the background shows the sensitivity of a typical CCD sensor. The most important artifical emission lines are shown in orange. The artifical light pollution is dominated by see mercury (Hg) and sodium (Na), which are used in nearly all streetlights. The most important emission lines from nebulas are shown in green. The most important lines are from ionized Hydrogen (H-alpha and H-beta) and double ionized oyxgen (OIII). The major emission lines of artifical light pollution: | Hg 435,8nm | Hg 546,1nm | Hg 577,0nm | Hg 578,1nm | | Na 589,0nm | Na 589,6nm | Na 615,4nm | Na 616,1nm | The major emission lines of nebulas: H-β 486,1nm | OIII 495,9nm | OIII 500,7nm | H-α 656,3nm Quality Characteristics of Astronomik Filters Superior Substrate: Astronomik filters consist of a precision polished substrate on which the actual filter, in the form of very thin (dichroic) interference layers, is applied. Because of these high quality measures Astronomik filters will in no way reduce the performance of your optical system. And contrary to common experience with other manufacturers´ filters, with Astronomik filters stars remain fine needle points of light! Coating: Astronomik filters consist of up to 130 layers deposited on top of the completely transparent carrier glass. These layers work as the actual filter and as an antireflective coating. Durability: Astronomik filters are completely scratch resistant, and not sensitive to moisture, dew, or high humidity. With others’ filters, after a few years, you start to notice their filter is no longer up to its full capability. Not so with Astronomik filters which maintain their ‘brand new’ transmission specifications year after year. And, because of Astronomik’s extraordinarily resistant coating technology, our filters come with a 10year warranty. Astronomik filters are highquality accessories for visual observing which will significantly expand your observing opportunities. After many years of use your Astronomik filters will be an accessory which will be ready to give you the same joy you experienced many years earlier when they were new. Now that’s an investment worth making! Compatible Canon EOS R APS-C cameras Model Compatibility Canon EOS R7 Canon EOS R10 Canon EOS R50 Canon EOS R50 V Canon EOS R100 Non-compatible Canon lenses Model Compatibility Canon RF 14mm f/1.4 L VCM Canon RF 28mm F2.8 STM Canon RF 35mm F1.8 IS Macro STM Canon RF 85mm F1.2L USM Canon Extender RF 2x Canon Extender RF 1.4x Astronomik filters are diffraction-limited, ensuring that the optical performance (resolution and contrast) of your telescope is not compromised. Thanks to the high-precision machining of the glas substrate, all Astronomik filters are parfocal. The wedge errors are far below all common tolerances. Therefore, all issues concerning focal distances and the exact alignment of images from each color channel are 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 and MaxFR coatings are 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. Technical Specifications 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 Parfocal with other Astronomik filters Diffraction-limited Optimized spectral windows Delivered in a high-quality, long-lasting filter box Made in Germany In the Box CLS filter, at selected size. Manual & Warranty Astronomik 10 year warranty
