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OPTOLONG 2inch Filter Astronomy Telescope SII-CCD 6.5nm Narrow-Band Filter for Deep Sky

4.6 (1) Write Review
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$199.00

$ 98 .99 $98.99

In Stock

About this item

  • Filter Manufacturing Processes and Parameters:
  • 1.Filter substrate is fine-optically polished to 1/4 wave and <30 parallelism over both surfaces
  • 2.Surface quality, according to MIL-O-13830, is 60/40
  • 3.80% transmission at SII line 672nm
  • 4.Infrared wavelength 700-1100nm cut-off
  • 5.0.1% transmission Hg at 435nm and 578nm
  • 6.0.1% transmission Na at 589nm
  • 7.High value transmission of pass-band and optical density of off-band is assured through Optolong's planetary rotation system, a homogenous and precise coating procedure
  • 8.Thin metal cells have a clear aperture of 26mm for 2" filters
  • 9.Each filter comes with a plastic case with high pressure EVA case lining


1.The Optolong 2" Filters are 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. The filter cell is made of lightweight, strong metal and is CNC machined, sand-blasted; black anodized, and then laser engraved. The result is a super thin filter cell that will produce a clear aperture of 26mm.


Reviewer1560
Reviewed in the United States on June 13, 2024
Didn't seem to notice any halos at 600s exp, good enough for me.
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