The Astronomik CLS CCD is suitable under light-polluted skies for DSLR Cameras and enhances the contrast between all deep-sky objects and the background.
The CLS-CCD Filter enhances the contrast between astronomical objects and the background. Compared to UHC filters, a greater amount of light will pass the filter due to the wider transmission curve. The stars in this filter will be less dimmed than other similar filters. This filter has been optimized to block as much spurious light as possible while simultaneously providing the best performance for 'useful' light. This is a fantastic filter for DSLR, CCD, film B/W photography, and even observation of deep-sky objects with telescopes or photo lenses of all apertures f/3 and above.
This filter completely blocks emissions lines from artificial light sources such as streetlights as well as the airglow. But not to worry, all emission lines we find to be most important pass through just fine! The supplementary IR-blocking layer also allows the use for DSLR- and Webcams without an integrated IR-block filter. You will see that this filter brings better resolution of double stars as well.
If you plan to create color images from emission line data, the CLS-CCD filter is a great choice.
The Astronomik UHC filters offer a transmission rate of¬†95%¬†for H-beta (486nm), OIII (496nm), OIII (501nm), and¬†97%¬†for H-alpha (656nm). For optimal performance, these filters are best used with telescopes with focal ratios between f/3.5 and f/10. These are also both scratch-resistant and not sensitive to humidity or aging with their excellent craft materials. These filters will not reduce the optical performance of your telescope and are parfocal with other Astronomik filters
Another major advantage of the Astronomik UHC filter is the high optical quality of the filter glass. When using Astronomik UHC filters you will quickly notice the same needle-sharp stars which you are familiar with from your astronomical instrument without any filter!
- Visual Observing (Dark Skies): Very good for all telescopes and has a high exit pupil
- Visual Observation (Urban Skies): Very good for telescopes from 100mm aperture and up
- CCD Photography: Good when used with an additional IR-block-filter
- DSLR Photography: Good. Color balance is slightly shifted but contrast is enhanced
- DSLR Photography (Astro Modified): Very good with near perfect color balance
- DSLR Photography (MC Modified): Good when used with an additional IR-block-filter
- Webcam / Video (Planets): Unsuitable
- Webcam / Video (Deep Sky): Good if light pollution is a big problem