Optolong OIII 25nm 2" Mounted Filter

Optolong OIII 25nm 2" Mounted Filter

DESCRIPTION

The Optolong 2" OIII 25nm filter is specifically designed for visual observation of nebulae, including emission, planetary and supernova remnants. It enhances contrast by transmitting a narrow band centered at 500 nm while blocking unwanted light pollution and irrelevant wavelengths. It is most effective with telescopes of 6 inches or more in aperture.

Constructed from precision-polished Schott B260 optical glass, this filter uses a multilayer anti-reflection coating applied via ion-assisted deposition. Its CNC-machined anodized metal cell is ultra-thin and threaded, offering a wide clear aperture of 45 mm for optimal light transmission.

TECHNICAL SPECIFICATIONS

• Type: OIII narrowband interference filter

• Intended use: visual observation only

• Bandwidth: 25 nm centered at 500 nm

• Transmission: 90% at 495.9 & 500.7 nm

• Blocking: <0.1% at 435, 578, 589 nm

• Glass: 2 mm Schott B260

• Coating: multilayer AR, ion-assisted deposition

• Polishing: 1/4 wave, <30" parallelism

• Housing: CNC machined, anodized black, threaded

• Diameter: 2" (50.8 mm), 45 mm clear aperture

• Shape: round

• Model: OIII-200

• Brand: Optolong

• Included: plastic case with EVA lining