Optolong L-Pro filter 2" The L-Pro is a multi-bandpass broadband light-pollution filter that keeps natural colour balance. It suppresses the main artificial lines (Na 589 nm, Hg 435 and 578 nm) while staying highly transparent at H-beta, OIII, H-alpha, NII and SII, suiting galaxies, reflection nebulae and star clusters as well as visual use.
Manufacturer model: Optolong L-Pro 2" · Specifications checked against manufacturer data on 2026-11-03
The L-Pro is a multi-bandpass broadband light-pollution filter that keeps natural colour balance. It suppresses the main artificial lines (Na 589 nm, Hg 435 and 578 nm) while staying highly transparent at H-beta, OIII, H-alpha, NII and SII, suiting galaxies, reflection nebulae and star clusters as well as visual use.
| Format | 2" mounted |
|---|---|
| Type | Multi-bandpass broadband light-pollution filter |
| Spectrum | 380–750 nm |
| Blocked lines | Na 589 nm; Hg 435 and 578 nm |
| High transmission | H-beta 486, OIII 496/500, NII 654/658, H-alpha 656, SII 672 nm |
| Material | Optical glass |
| Surface quality | 60/40 (MIL-O-13830) |
| Transmitted wavefront | λ/4 |
| Parallelism | <30" |
Multi-layer anti-reflection coating on a non-cemented substrate, applied by ion-assisted deposition for durability and a stable centre wavelength with temperature.
Optolong L-Pro 2" mounted. Not the camera clip-in or 77/82 mm versions.
| Spectrum | 380–750 nm |
|---|---|
| Blocked lines | Na 589 nm; Hg 435 and 578 nm |
| High transmission | H-beta 486, OIII 496/500, NII 654/658, H-alpha 656, SII 672 nm |
Data sheet
Optolong L-Pro filter 2" The L-Pro is a multi-bandpass broadband light-pollution filter that keeps natural colour balance. It suppresses the main artificial lines (Na 589 nm, Hg 435 and 578 nm) while staying highly transparent at H-beta, OIII, H-alpha, NII and SII, suiting galaxies, reflection nebulae and star clusters as well as visual use.
Manufacturer model: Optolong L-Pro 2" · Specifications checked against manufacturer data on 2026-11-03
