Castell CLS (City Light Supression) Filter, 1.25"
Castell CLS Filter for eyepieces, cameras and filter wheels with 1.25-Inch (31.7 mm) nosepiece
The Castell CLS filter blocks the part of the spectrum where street lights (sodium, mercury lamps) emit light.
This filter comes in an extremely low profile cell with just 4.5mm thickness (or if we also calculate with the male threaded part, it's still just 7mm).
- when used visually with an eyepiece, the eyepiece will sit deaper in the amici prism or mirror diagonal due to the thin construction.
- filters with normal height might sometimes stack in thin filter wheels, but this filter will still be fine.
Please note, this filter cannot be stacked with other filters as there is no thread on the telescope side.