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FLI - 28mm LRGB Research Grade Filters

Model#: RG 28D LRGB

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Availability: In stock


Manufactured by: Finger Lakes Instrumentation




  • FLI Research Grade filter sets are par focal to F4.5 (individual filters are also available, contact FLI)
  • Size: 28mm
  • Shape: round
  • Thickness: 3mm +/-0.1mm
  • Bandwidth: N/A
  • Parallelism: 30 second or better
  • Surface Flatness: 1/4 wave per inch



Product Series

Our high transmission filters are manufactured in the United States with the highest quality fabrication techniques available. We offer a full line of filter types and sizes. Complete sets are available as well as individual filters in both round and square shapes.


AR: Durable AR coatings on both exterior surfaces over applicable transmission range

Scratch Dig: 60/40 or better (max scratch width 0.006mm, max dig 0.40mm)

Transmitted wavefront @ 633nm: Better than 0.25 wave/inch

Wedge: Better than 30 arcsec

Thickness: 5 +/- 0.05mm, par focal +/- 0.2mm, (filters start par focal +/- 0.1mm per recipe)

Additional Information

Name FLI - 28mm LRGB Research Grade Filters
Manufacturer Finger Lakes Instrumentation
Model RG 28D LRGB
Parallelism 30 second or better
Shape Round
Size 28mm
Surface Flatness 1.25 wave per inch
Thickness 3mm +/-0.1mm