Fitro Optolong OIII 18nm 2" OIII 18nm 2" Fitro OIII 18nm 2"

Fitro Optolong OIII 18nm 2" OIII Narrowband Filters

OIII narrow band filters are designed for observing nebulae emitting light at 495.9 nm and 500.7 nm corresponding to OIII emission lines.

This 18 nm Optlong O-III filter is perfect for observing emission nebulae, planetary nebulae and supernova remnants. Many images of planetary nebulae and supernovae are taken only with H-alpha and OIII filters. They show great structural detail, but have natural, RGB-like colors.

By selectively reducing the transmitted wavelengths, they increase the contrast of the nebulae and suppress the effects of urban lighting, including wavelengths from mercury vapor lamps and high- and low-pressure sodium lamps, as well as natural light caused by the emission of neutral oxygen in the atmosphere (skyglow). It is therefore suitable for observing bright nebulae (such as the Orion nebula M42) in places with strong light pollution.

Optolong now offers this second version of its O-III filter with a bandwidth of 18 nm. More selective than the 25 nm model, it offers less brightness, but more contrast. It is therefore suitable for use in instruments with large diameters (at least 300 mm).

The ultra-thin filter cell minimizes vignetting by allowing a diaphanous aperture of 45 mm for 2" (50.8 mm), having been fabricated in aluminum using CNC machines of extreme manufacturing precision.

Recommended uses:

• Visual observation (rural sky): significant contrast enhancement in emission nebulae.
• Visual observation (urban sky): Significant contrast enhancement in emission nebulae.
• CCD photography: For use in conjunction with an anti-IR filter.
• DSLR photography (unmodified): Significant contrast enhancement in emission nebulae.
• DSLR photograph (modified): Significant contrast enhancement in emission nebulae.
• Planetary photography (from video clips): Incompatible
• Webcam / video (deep sky:) Suitable for cases where light pollution is significant and the objects to be observed emit in O-III.

Fitro Optolong OIII 18nm 2"OIII