The Optolong LRGB 36 mm Filter Set (Optolong, SKU: LRGB-36) is designed to provide maximum contrast and extremely high gradient separation, allowing clear and natural color differentiation in astrophotography.

Key features

• spectrum divided into four components: luminance (L), red (R), green (G) and blue (B)
• high transmission in the blue and green bands for OIII emission lines, enabling very high imaging efficiency and natural color rendition
• gap between green and red filters blocks the primary sodium light pollution line at 589nm
• improved color balance and separation through effective suppression of unwanted wavelengths
• the white line in the transmission graph represents the luminance filter response

Main use and performance

• excellent performance with monochrome CCD and CMOS cameras
• suitable for Deep Sky and planetary imaging
• RGB imaging with equal contribution from each channel, important for accurate color reproduction
• full availability of raw sRGB image data when used with monochrome cameras

Technical specifications

• substrate material: Schott optical glass
• thickness: 2.0 mm
• surface quality: 60/40 (according to MIL-O-13830)
• fine optical polishing ensuring 1/4 wave accuracy and <30 arcseconds parallelism over both surfaces
• transmission: 95% at bandpass
• infrared cut-off: 700–1100 nm
• precision off-band blocking
• multi-layer anti-reflection coating
• non-cemented optical substrate coating
• electron-beam evaporation with ion-assisted deposition for durability, scratch resistance and CWL stability independent of temperature changes
• planetary rotation system ensuring coating homogeneity, high pass-band transmission and high off-band optical density
• ultra-thin filter cell minimizing vignetting and maximizing clear aperture
• filter cell material: Aerometal
• precision CNC machining
• sand-blasted and black anodized finish
• extinction treatment to prevent internal reflections
• laser engraving with no fading