This Optolong LRGB filter set is designed for maximum contrast and with extremely high gradients for clear differentiation of colors. The LRGB filter set divides the spectrum into its components: red, green, blue and luminance. The OIII emission overlaps on blue and green filters with maximum transmission to allow high efficiency and natural color imaging. A gap in the transmission's spectrum of green and red filters serves to block out the primary Sodium light pollution line at 589nm and improves color balance as well as separation.

Main Use and Performance

It works well with debayered monochrome CCD cameras. Suitable for deepsky and planetary CCD imaging. RGB-imaging allows equally weighted factors for each channel, that is very important for automated imaging. An ideal raw material for image processing in the sRGB color space can be achieved with this LRGB filter set and a monochrome CCD camera.

WARNING:

Optolong filters are not designed for solar observation. DO NOT LOOK AT THE SUN WITH ANY OPTOLONG FILTER as permanent eye damage will be the result.

Technical Data

• Schott substrate material
• Glass thickness 2.0 mm (available sizes: 1.25” / 2” / 36mm)
• Surface Quality: 60/40 (Refer to MIL-O-13830)
• Fine-optically polished to ensure accurate 1/4 wavefront and < 30 seconds parallelism between the two surfaces
• 95% transmission
• Infrared wavelength 700-1100nm cut-off
• Precision off-band blocking

Filter Cell

• Ultra-thin filter cell minimise vignetting by maximising possible clear aperture (clear aperture is 26mm for 1.25” size and 45mm for 2” size)
• Aerometal Material
• Precise CNC Machining
• Sand Blasting Process
• Black Anodized Finish
• Extinction Treatment to Prevent Reflection
• Laser Engraving No Fading

Available Sizes

• Standard 1.25” & 2”
• Round 36mm Unmounted
• Clip Filter Series: not available as LRGB imaging is not practical for dSLR cameras

Packaging

• Plastic PP Case
• Imported High Pressure EVA Case Lining
• Silver Cardboard Box
• High Density Sponge Carton Lining

Optical Coating

• Multi-layer anti-reflection coating
• Non-cementing optical substrate coating
• Electron-beam gun evaporation with Ion-assisted deposition coating technology for durability and resistance to scratching, as well as stability on CWL (central wavelength) no deviation affected by temperature change.
• Planetary rotation system offers precision and homogeneity of coatings ensuring high value on transmission of pass-band and Optical density of off-band. (Please note, "planetary rotation system" is a type of optical coating process and does not refer to the astronomical system describing the motion of the planets in our solar system.)

The Major Emission Lines of Nebulae: H-α 656.3nm, H-β486.1nm, OIII 495.9nm, OIII 500.7nm 
The Major Emission Lines of Artificial Light Pollution: Hg 435.8nm, 546.1nm, 577nm, 578.1nm, Na 598nm, 589.6nm, 615.4nm, 616.1nm