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Black 2-inch threaded astronomy filter in metal cell

Celestron

Celestron 2" Oxygen III Narrowband Filter 496/501nm #93624

SKU CH-D0N9-Y1RT7

Isolates 496 nm and 501 nm oxygen-III emission lines from nebulae while blocking the full 400–700 nm visible spectrum to suppress star halos

  • TypeMonoculars
  • ColorBlack
  • FeaturesThe Oxygen III 2 Inch Narrowband Filter isolates just the tw
  • Isolates key O-III nebula lines
  • Blocks full visible spectrum 400-700nm
  • Eliminates coloured halos around stars
  • Reveals faint planetary nebula detail
  • Durable vacuum-deposited coating technology

Purpose and Audience

The Celestron 2" Oxygen III Narrowband Filter #93624 is designed for astrophotographers who target planetary and emission nebulae. It isolates the two doubly-ionized oxygen lines to reveal intricate structures in objects such as the Veil, Ring, Dumbbell, Crescent and Orion nebulae.

Spectral Transmission Limits

The ultra-hard vacuum-deposited coating blocks all visible light from 400 to 700 nm while passing only the 496 and 501nm oxygen lines. This hard cutoff eliminates the unnatural coloured halos that often appear around bright stars with less sophisticated O III filters.

Capacity and Headroom

The filter delivers maximum contrast for faint OIII photons, making it highly effective for deep-sky imaging of the named nebulae. It runs out of utility on targets that do not emit strongly at the two isolated oxygen wavelengths, such as reflection nebulae, galaxies or broadband objects.

Highlights

  • Isolates key O-III nebula lines
  • Blocks full visible spectrum 400-700nm
  • Eliminates coloured halos around stars
  • Reveals faint planetary nebula detail
  • Durable vacuum-deposited coating technology

Specifications

BrandCELESTRON
TypeMonoculars
ColorBlack
FeaturesThe Oxygen III 2 Inch Narrowband Filter isolates just the two doubly-ionized oxygen lines (496 and 501nm lines) emitted by planetary and emission nebulae, while blocking the rest of the overall spectrum of light.. Each filter has an ultra hard, vacuum-deposited coating carefully designed to block all of the visual spectrum ranging from 400 to 700 nm.. This eliminates the un-natural colored halos surrounding bright stars common with Oxygen III filters of a less sophisticated coating technology...

Questions about this item

Which filter size matches my 2" eyepiece or camera adapter?

The filter is built for a standard 2" threaded barrel, so it screws directly into any 2" eyepiece, diagonal or astro-camera nosepiece without additional adapters.

What does isolating the 496 and 501nm oxygen lines actually show me?

It transmits only the two doubly-ionized oxygen wavelengths emitted by planetary and emission nebulae, suppressing the rest of the 400–700nm spectrum to reveal structures in objects such as the Veil, Ring, Dumbbell, Crescent and Orion nebulae.

How does the vacuum-deposited coating affect bright-star halos?

The ultra-hard coating blocks all visible light from 400 to 700 nm outside the O III lines, eliminating the unnatural coloured halos that simpler O III filters often produce around bright stars.

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