L-eXtreme

Optolong L-eXtreme is a dual-narrowband filter (OIII-7nm & Ha-7nm) designed to exclusively transmit the key nebula emission lines of OIII (500.7nm) and Hα (656.3nm). By effectively blocking all other light pollution emission lines, it ensures that only the signals from OIII and Hα elements are captured during imaging, achieving maximum effective transmission to deliver clean, high-contrast OSC nebula data under light pollution and even with some moonlight.

🔑 Key Features

• Dual 7 nm windows centred at OIII (~500.7 nm) and H-α (~656.28 nm) for tight nebula contrast.
• Strong out-of-band blocking – OD4 from 300–1000 nm to suppress LP glow and stray light.
• Durable coatings – multi-layer AR with ion-assisted deposition for stability and scratch resistance.
• Format – 2″ mounted (M48×0.75); 1.85 mm optical glass substrate.

✅ Why Choose This Product?

• High contrast – narrower dual bands yield cleaner separation and darker backgrounds in suburban skies.
• Straightforward workflow – capture H-α & OIII detail with a single filter (no mono camera required).
• Field-ready build – coated, threaded 2″ cell compatible with standard M48 accessories.