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.
It blocks the light of mercury and sodium-vapor lamp spectral lines (street lights), while letting the largest part of 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, pass through the filter unhindered.
190 aud including shipping........
used once............. then i moved to a better sky...
thanks