Antlia OIII 2.5nm 2"

Antlia OIII 2.5 nm Ultra Narrowband — 2" mounted

Antlia's 2.5 nm Ultra series is its narrowest narrowband line. This OIII filter isolates the 500.7 nm doubly ionised oxygen line for maximum contrast and star-size control, even under heavy light pollution or a bright Moon.

Precision construction

The filter is made on 2 mm quartz-glass substrate, held to ±0.05 mm, and blocks out-of-band light to OD5. Antlia recommends it for optics at f/3.5 and slower.

Specifications

Manufacturer documentation

Antlia 2.5 nm Ultra narrowband filters

Compatibility notes

2.5 nm Ultra series, not 3 nm Pro or 4.5 nm Edge. f/3.5 and slower. Cell dimensions not published.

Additional specifications