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⚠️ Our store is currently closed for the Holiday Season until 28 Jan ⚠️ Orders received during our closure will be posted upon our return from 30th January. 🎁 Free Shipping on all orders with discount code: HOLIDAYS at checkout 🎄 Thank you & Happy Holidays! 🎅

Optolong 3nm Ultra Narrowband 2" SHO Filter Set

Save $640.00 Save $640.00
Original price $1,899.00
Original price $1,899.00 - Original price $1,899.00
Original price $1,899.00
Current price $1,259.00
$1,259.00 - $1,259.00
Current price $1,259.00
New 3nm Ultra Narrowband Astronomy Filters from Optolong

Narrowband filter set including SII (S) 3nm, Ha (H) 3nm and OIII (O) 3nm filters.

Narrowband imaging can be done with the moon up or in heavy light pollution so you can make the most of every clear night.

Data from each narrowband filter can be combined to create a final colour image, a common combination is HOO using H-alpha for the red and OIII for the green and blue channels. It can also be useful to use H-alpha data blended into an RGB data set to enhance the contrast and structural detail whilst maintaining a natural look.

H-Alpha 3nm Filter: The most popular narrowband filter allowing 3nm bandwidth of light centred on a wavelength of 656nm to pass through. Low transmission of other wavelengths of light specifically those produced by artificial light including mercury vapour, both high and low pressure vapour lights and unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e.skyglow). Great choice for higher contrast and revealing subtle nebula details. 

OII 3nm Filter: Designed for observing / imaging nebulae allowing 3nm bandwidth of light to pass centred on a wavelength of 500nm which corresponds to the OIII emission line. Low transmission of other wavelengths of light, specifically those produced by artificial light including mercury vapour, both high and low pressure sodium vapour lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow). OIII emits at 495.9nm and 500.7nm which represents a blue-green colour. Many images of planetary nebula and supernovae remnants are taken with only H-Alpha and OIIII filters. They show great structural details with natural colours, similar to an RGB image.

SII 3nm Filter: Designed for observing / imaging nebulae allowing 3nm bandwidth of light to pass centred on a wavelength of 672nm. Low transmission of other wavelengths of light, specifically those produced by artificial light including mercury vapour, both high and low pressure sodium vapour lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow).

IMPORTANT: Filters manufactured by Optolong are NOT designed for observing or photographing the Sun. DO NOT use Optolong filters to observe or photograph the Sun. If you do it will result in permanent eye damage! 

FEATURES

  • 85%+ transmission at passband / Precision off-band blocking
  • Infrared wavelength 700-1000nm blocked
  • 0.1% transmission of off-band, specifically the major emission lines of artificial light pollution (i.e. Na 589nm, Hg 435nm and 578nm)

  • Suitable for use with mono CCD and CMOS cameras
  •  2" mounted or 36mm unmounted sizes.
  • Supplied in a protective plastic case with EVA foam lining
  • Optical Glass 2mm thick in 36mm filters, 1.85mm in 2" filters.
  • Fine-optically polished on both sides - ensures accurate λ/4 wavefront and <30 seconds parallelism over the both surfaces

Transmission Chart

SII Line: H-alpha, 3nm centred at 656nm.

Green Line: SII, 3nm centred at 672nm.

Blue Line: OIII, 3nm centred at 500nm

Technical Data

  • Schott substrate material
  • Thickness 2.0 mm in 36mm filters, 1.85mm in 2" filters.
  • Surface Quality: 60/40 (Refer to MIL-O-13830)
  • Fine-optically polished to ensure accurate 1/4 wavefront and <30 seconds parallelism over the both surfaces
  • 85%+ transmission at passband
  • Infrared wavelength 700-1000nm cut-off

  • Precision off-band blocking

Coating Parameter

  • Multi-layers 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

Filter Cell

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