Astronomik CLS filters are suitable under light-polluted skies for DSLR Cameras which have not been modified for astronomical use. For modified DSLRs, use Astronomik CLS-CCD filters.
The Astronomik CLS 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 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.
If you wonder what to expect from the CLS, you might want to watch this video from Kamil Pekala
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.
More information about the visual Astronomik filters
More information about the photographical Astronomik filters
- 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
- 92% transmission at 486nm (H-beta)
- 92% transmission at 496nm (OIII)
- 92% transmission at 501nm (OIII)
- 97% transmission at 656nm (H alpha)
- pass from 450 to 540nm and beyond 650nm
- Parfocal with other Astronomik filters
- Glass thickness: 1mm
- Completely resistant against high humidity, scratches and aging effects
- Diffraction limited, the filter will not reduce the optical performance of your telescope!
- Astronomik filters are delivered in a high-quality, long lasting, filter box
- Since 2008 we do ship filters with a completely new design. Any kind of halo or strange reflection is a matter of past
Sizes Available From Astronomik - Please ask us if we don't have a price listed for the one you would like
T-thread cell (M42x0.75)
SC-cell (2" / 24TPI)
EOS APS-C Clip-Filter
EOS M Clip-Filter
EOS XL Clip-Filter
Sony alpha Clip-Filter
Nikon XL Clip-Filter
Pentax K Clip-Filter