Baader Filters Ultra-Narrowband 4.5nm OIII CCD-Filter 50x50mm

OIII filters selectively permit light with a wavelength of 501 nanometres, corresponding to the spectrum lines of doubly ionized oxygen. This characteristic emission is emitted by planetary nebulae and certain emission nebulae, allowing these celestial objects to remain visible while filtering out other wavelengths. This filtration enhances contrast, revealing faint nebulae that were previously imperceptible.

In astrophotography, these filters are most effective when paired with monochrome cameras. Ideally, images captured using OIII filters should be combined with those taken using H-alpha and SII filters. This combination produces images that depict faint nebulae clearly and with high contrast.

Specifications:

Capacity:

Central Wavelength: 502 nm

Half-value Width: 4.5 nm

Optical Length: 3 mm

Coating of Optical System: Dielectric

Frame: Unmounted

Filter Size: 50 x 50 mm

General:

Type: Filters

Type of Build: Line filter

Area of Application:

Useful for Photographs: Yes

Planetary Nebulae: Yes