The CLS Light Pollution Filter - T Thread by Astronomik:
The Astronomik CLS is a budget filter for visual observation, Black and 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.
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 Astronomik CLS Light Pollution Filter is good for use under both dark and urban skies for reducing light pollution made by mercury-vapor lamps. For film photography and modified DSLR use, the CLS filter gives good performance and near perfect color balance. While this filter does perform well with webcam and video equipment under light polluted skies, it is not suitable for planetary use.
Astronomik CLS Light Pollution Filter - T Thread Features:
- 92-percent transmission at 486 nm (H-beta)
- 92-percent transmission at 496 nm (OIII)
- 92-percent transmission at 501 nm (OIII)
- 97-percent transmission at 656 nm (H-alpha)
- Pass from 450 to 540 nm and beyond 650 nm
- Parfocal with other Astronomik filters
- Glass thickness: 1 mm
- 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
OPT Product Number: AK-CLS-T