BA2458395 Baader O-III Nebula Filter - 1.25"- 10nm HWB

1.25" O-III filter - observation of high contrast mists

O-III filters are particularly suitable for planetary nebulae. In the light of the triply ionized oxygen (O [III]), these interesting nebulae develop special structures. But even in gas mists O-III regions are often stored. For example, a gas mist with the O-III filter can show completely different structures than with the UHC filter or even without a filter.

The Baader O-III is particularly narrow-band, it has only 10 nm bandwidth. We recommend the use from about 200mm opening. It is a very good addition to the broadband UHC-S filter from Baader.
The transmission curve shows a very narrow transmission window of only 8nm - exactly in the O-III range at 501nm.

With the O-III filter, even with extreme stray light exposure through cities, successful fog observations can be made. The background is jet black even at low magnifications.

The filter is dielectrically tempered and therefore resistant to aging. He is also very robust and scratch-resistant. In addition, highest imaging quality is guaranteed by plano-optically polished surfaces.