Optolong LRGB CCD Filter Set - 31mm unmounted

The Optolong LRGB Filter Set comes four 31mm unmounted filters, including Red, Green, Blue, and Luminance. They are designed for de-bayered monochrome CCD and CMOS cameras and work great for both planetary and deep-sky imaging. Like all Optolong filters that are designated as “CCD”, this filter set blocks infrared wavelengths from 700nm to 1100nm so you don't need a separate IR-Cut filter.

The transmission of each filter is designed for maximum contrast and beautiful results. There is a gap between the green and red filters that improve color balance and separation by blocking out the Sodium line at 589nm. Also, OIII emission is allowed to overlap on the blue and green filters for more natural color.

The Optolong 31mm Unmounted LRGB Filter Set is made with Schott glass that has been multi-coated with an ion-assisted deposition technology to ensure scratch resistance and stability on the central wavelength or CWL. This filter set is designed to be used in color filter wheels that accept 31mm unmounted filters. It doesn't matter which way you drop them into the filter wheel. The filters are unmarked and either side can face up or down.

Quality Filter Materials:

• Schott B260 substrate material from Germany, 2.0mm thick
• Multiple layers of anti-reflection non-cementing coatings applied via electron-beam gun evaporation with Ion-assisted deposition

Optolong Filter Manufacturing Processes and Parameters

• Filter substrate is fine-optically polished to 1/4 wave and <30 parallelism over both surfaces
• Surface quality, according to MIL-O-13830, is 60/40
• 95% transmission at bandpass
• Infrared wavelength 700-1100nm cut-off
• Optolong’s planetary rotation system is a homogenous and precise coating procedure that ensures both high transmission of pass-band and optical density of off-band
• Each filter comes with a plastic case with high pressure EVA case lining