Focal Length Max.: 0 mm, Magnification: 0×, Telescope Type: Accessory
- Isolates doubly ionized oxygen lines (496 and 501 nm)
- Enhances contrast in emission and planetary nebulae
- Ultra-hard vacuum-coated surface blocks 400 to 700 nm
- Eliminates unnatural color fringing around bright stars
- Fits 1.25-inch eyepieces and accessories
- Ideal for astrophotography and nebula observation