{"id":29063,"date":"2025-09-20T20:04:16","date_gmt":"2025-09-20T18:04:16","guid":{"rendered":"https:\/\/www.telescoop.nl\/?post_type=product&p=29063"},"modified":"2026-08-25T15:10:45","modified_gmt":"2026-08-25T13:10:45","slug":"optolong-oiii-filter-3nm-2-inch","status":"publish","type":"product","link":"https:\/\/www.telescoop.nl\/en\/optolong-oiii-filter-3nm-2-inch\/","title":{"rendered":"Optolong OIII Filter 3nm 2 inch"},"content":{"rendered":"

Optolong OIII Filter 3nm 2 inch: a single emission line, maximally isolated<\/strong><\/h2>\n\n\n\n

This filter isolates the OIII emission line around 500.7 nm with a half-width of 3 nm. All other light, including streetlights and moonlight, is blocked. This results in a deep dark sky background, maximizing the visibility of nebula structures at this wavelength. At 3 nm, this is Optolong's narrowest OIII version for maximum contrast.<\/p>\n\n\n\n

Narrowband filters are the foundation of monochrome camera photography: you photograph the lines separately and combine them into color composites, such as the well-known Hubble Palette (SHO).<\/p>\n\n\n\n

\"Optolong<\/figure><\/figure>\n\n\n\n

What you use this filter for<\/h4>\n\n\n\n

Designed for planetary nebulae, supernova remnants like the Veil Nebula, and oxygen-rich parts of emission nebulae. Because light pollution is virtually completely blocked, you can also photograph from the city and in moonlight with this.<\/p>\n\n\n\n

Technology<\/h4>\n\n\n\n

The Schott glass is finely optically polished and features multi-layer ion-assisted coatings: high transmission in the passband, strong blocking outside of it, and a central wavelength that remains stable with temperature changes. The thin metal mount minimizes vignetting.<\/p>\n\n\n\n

Featured accessories<\/h3>\n\n\n\n

Combine this filter with the other lines (H-alpha, OIII, and SII) for complete narrowband composites. A bright focus filter speeds up focusing.<\/p>\n\n\n\n

For whom yes and for whom no<\/h3>\n\n\n\n