Baader O-III CCD Narrowband Filter 8.5 nm - 2" filter thread

Baader O-III CCD Narrowband Filter 8.5 nm

Narrowband O-III filters are very often used for astrophotography. They provide very good contrast when photographing diffuse nebulae which emit [O III] light, like the Cirrus Nebula. The Baader O-III filter blocks the entire visible light, except a small passage in the blue-green [O III] light. This offers some advantages:

♦ The entire stray light of cities is hidden, so beautiful photographs are possible even close to a city.
♦ Star images from refractor telescopes are significantly improved, the stars become sharper.
♦ Combined with Baader H-alpha and S-II CCD narrowband filters, exciting false color images are possible.


Baader narrowband filters - application areas:

These filters have revolutionised astrophotography. It is possible to record very dim nebulae even for small telescopes. In this case only light of the nebula is transmitted and unwanted light is blocked. The gain in contrast is enormous.

Colour fringes from the telescope (chromatic aberration) are also reduced significantly or even eliminated completely. The stars are much smaller anf seem almost like punched.

These properties are achieved by a complex filter design. Baader filters are manufactured according to professional standards and provide adequate performance.

♦ Maximal contrast through steep edges.
♦ Dual cavity design for focal ratio f/3 to f/10
♦ Best sharpness through plane-parallel surfaces.
♦ Resistant to aging through optimal sealing also at the edge.




Correct mounting of unmounted Baader filters

All unmounted Baader filters for which the direction of the filter is relevant have a small arrow placed at the edge. This arrow has to point to the telescope optics / sky. If there is no arrow, it does not matter how you mount the filter.

♦ Baader 8.5 nm O-III filter
♦ High-quality system box - stackable