The 36mm CLS Light Pollution Filter - Mounted in Low Profile Non-Threaded Cell 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 CLS filter is suitable for use with telescopes of all aperture sizes and even works well with binoculars.
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.
Now Mounted in Low Profile Non-Threaded Cell: Sometimes unmounted CCD filters can be hard to handle. The smaller diameters, such as this 36mm CLS filter, can be especially difficult to pick up and insert or remove from the filter wheel, and that can lead to possible damage as well as unwanted reflections from incorrectly installed filters. Astronomik has solved this problem by mounting their 31mm and 36mm filters in a low profile (3mm) non-threaded cell. O-rings, washers, or spacers are no longer required to hold the filter in place, and because the cell is only 3mm thick, it works well in all appropriately sized filter wheels. Mounted 31mm and 36mm Astronomik filters will also play nice with unmounted versions in the same carousel.
Astronomik CLS Light Pollution Filter - 36mm Round Mounted Features:
- 92-percent transmission at 486nm (H-beta)
- 92-percent transmission at 496nm (OIII)
- 92-percent transmission at 501nm (OIII)
- 97-percent transmission at 656nm (H-alpha)
- Pass from 450 to 540nm and beyond 650nm
- Parfocal with other Astronomik filters
- Glass thickness: 1mm
- Cell thickness: 3mm
- 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