Lumicon 1.25" OIII Filter

Lumicon 1.25" OIII Filter
Item # LU-LF3040
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  • The Lumicon 1.25" OIII filter boosts contrast by allowing just the Oxygen lines (or 496nm to 501nm) of light to reach your eye.
  • Brings out amazing detail in diffuse, planetary and very faint nebulae. See the Orion, Swan and Dumbbell nebula like never before!
  • Contrast boosting qualities make it a great choice to reduce light pollution.
  • Because the OIII filter has a very narrow bandpass, it will darken your overall view and therefore is not recommended for small aperture telescopes. Read more about suggested exit pupil requirements below.
  • Lumicon's individual inspections maintain rigorous quality control and each OIII narrowband filter features hard coatings that resist feather scratches.


About the Lumicon OIII Filter

The Lumicon OIII (Oxygen III) filter isolates just the two doubly ionized oxygen lines (496 and 501nm lines) emitted by diffuse, planetary and extremely faint nebulae.  By allowing this narrow-band of light pass through, you will notice a tremedous increase in contrast and brightness in these typically faint objects.  These qualities also make it a great choice for light-polluted skies.  An excellent addition to your observing arsenal, the 1.25" version easily threads into your 1.25" inch eyepieces and accessories. Objects like the Lagoon, Swan, Dumbbell, Ring and Veil nebulae will be tremendously enhanced with the OIII filter, particularly under light polluted skies.

Using thin-film dielectric coatings on optically flat glass, over 30 layers of different coating material are what make up Lumicon's narrow band filter series.    This method and the material used provide a very hard coated surface that resists hairline scratches and dings exceptionally well.    Consisting of two elements which sandwich these coatings, an anti-reflection coating is added to prevent ghosting. 


Optimum Exit Pupil

Exit pupil is highly dependant on the equipment you're using. Each Lumicon filter has an optimum exit pupil for peak performance.   By dividing the focal ratio of your telescope into your eyepiece's focal length, you are provided with the exit pupil measurement.  For example, an f/8 telescope using a 32mm eyepiece has an exit pupil of 4mm.  At 10-12nm bandpass, the OIII filter's best exit pupil range is 2-5mm under light polluted skies and 3-7mm under dark sky conditions.

Additional Information

Additional Information

Manufacturer Lumicon
Type of Filter Contrast Booster, Light Pollution Reduction, Oxygen III
Filter Usage Visual
Single or Set? Single Filter
Filter Size 1.25"
Filter Shape Round
Filter Mounted? Mounted
Warranty 1 Year Warranty
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