Some celestial objects only become visible through special nebula filters. This filter is one of them. OIII (pronounced "O-3") stands for Oxygen 3 - a line filter.
Line filters primarily block light from our urban streetlights (mercury vapor and sodium lamps). This allows observations to be made outside the city. The sky background becomes almost completely black (depending on city luminosity) and planetary nebulae stand out more clearly.
The filter is optically polished for the highest quality images. The half-width is only 10 nm (nanometers) and the transmission is over 90%. The filter can also be used well in front of the focal point (e.g. binocular coupling, zenith prism/mirror).
Tip: If you want to get into the world of nebulae, we always recommend using a UHC filter first (up to 4 inches objective aperture), as its field of application is much larger. As a second filter, then an O III filter.
However, keep in mind that each celestial object has its own filter as well as its own magnification. After all, you cannot bypass the two nebula filters (UHC-S and O III). The nebula filters largely determine whether you see an object or not.
A sophisticated, scratch-resistant multilayer hard coating ensures easy and trouble-free cleaning.
The elaborate filter mount with CNC-milled grip edge can be operated safely at any temperature and can also be combined with other filters.
- Effectively suppresses city light
- Visually applicable
- Average width of 10 nm (nm = nanometer)
- Flat-parallel polished substrate of fine optics (1/4 lambda)
- Scratch-resistant multilayer hard coating
- Resistant to aging due to sealed coating edge
- LPFC = low-profile filter cell (flat height; screwed height 6 mm)
- 1¼" = filter thread M28.5mm
- Baader filter box, stackable
Filter installation instructions Baader Planetarium:
As a general rule, for all photographic filters that are inserted into the optical path just before the focal point, the brightest/mirrored side of any filter should ALWAYS be pointed towards the telescope optics rather than the chip taking the image - so that total freedom of reflection can be achieved.
