Baader Filters Ultra-Narrowband 4.5nm OIII CCD-Filter 36mm

OIII filters only pass light at 501 nanometers wavelength. This corresponds to the spectral line of the doubly ionized oxygen . This line is emitted by planetary nebulae and some emission nebula, so that by means of this filter these objects remain visible while the rest is hidden. This effect increases contrast and makes faint fog visible.

Astrophotography: This filter is best used with monochromatic cameras. Ideally, you combine the recording by this filter with recordings by H-alpha and SII filters. The result is a picture that shows the delicate fog structures rich in contrast and clearly.

The particularly narrow-band filter is ideal for fast optical system up to f / 3.5 . Since even slower optics up to f / 8 handle this filter very well, it can be described as very versatile.