Optolong H-Beta 12nm Filter - 1.25" Mounted - HBTA12-125 is no longer available.
We recommend these products instead:
Optolong H-Beta 12nm Filter - 1.25”
The 1.25" Hydrogen-Beta 12nm Filter by Optolong enables you to visually explore the widely popular yet elusive California Nebula and Horsehead Nebula with a large-aperture telescope under the night sky. This H-Beta filter can also be used for imaging those same celestial objects as well as many others that emit light at 486nm.
This blue narrowband filter lets a 12nm bandwidth of H-Beta light, centered at 486nm shine through and blocks other wavelengths, including those responsible for both artificial and natural light pollution, including bothersome light caused by mercury and sodium vapor lamps. Natural skyglow, caused by neutral oxygen emission in our atmosphere, is also blocked, resulting in a black background sky.
The Optolong 1.25” H-Beta 12nm Filter is 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.
Quality Filter Materials:
- Schott B260 substrate material from Germany, 2.0mm thick
- CNC machined and black anodized aero-metal filter cell that is ultra-thin to provide largest clear aperture; Laser-engraved to prevent fading
- Multiple layers of anti-reflection non-cementing coatings applied via electron-beam gun evaporation with Ion-assisted deposition
Optolong Filter Manufacturing Processes and Parameters
- Filter substrate is fine-optically polished to 1/4 wave and <30 parallelism over both surfaces
- Surface quality, according to MIL-O-13830, is 60/40
- 80% transmission at H-Beta 486nm
- 0.1% transmission Hg at 435nm and 578nm
- 0.1% transmission Na at 589nm
- High-value transmission of pass-band and optical density of off-band is assured through Optolong’s planetary rotation system, a homogeneous and precise coating procedure
- Thin metal cells have a clear aperture of 26mm for 1.25” filters
- Each filter comes with a plastic case with high-pressure EVA case lining
Optolong is the Astronomy Filters division of Yulong Optics, an optical filter design, and processing company out of Kunming, China that has provided filters for over 700 optical companies since 1999. All Optolong filters pass European Union RoHS requirements and have been certified by TUV Rheinland and Bureau Veritas.
Optolong 1.25" H-Beta 12nm Filter
- Filter Case
Dimensions & Specifications
Filter Size: 31.75 mm (1.25")
Filter Type: Broadband Deep-Sky
Filter Shape: Round
Mounted or Unmounted: Mounted
We stand behind all the products we sell, and your satisfaction is our top priority. If you're not satisfied with the quality of your purchase, simply send the item back to us in its original packaging within 30 days of its delivery.
Return & Exchange Policy
At our site, returns are easy! You may return new, unused, and resalable items for a refund or exchange. Simply ensure that the item is returned in its original product packaging within 30 days of delivery.
Most Helpful Reviews
Most Critical Reviews
Displaying Reviews 1-10 of