Optolong 6.5nm sulphur-II narrowband filter is for astrophotographers who want to obtain the maximum contrast of nebulae while cutting out background emission and suppressing star lights. This filter covers the sulphur-II line where major emission is generated from emission type nebulae. This filter is also commonly used by astrophotographers to present their photos in Hubble Pallete.
Compared to LRGB imaging, SHO narrowband imaging works even under full moon or severely light polluted area. H-alpha exposures can also be combined with LRGB to achieve greater details in the nebulae structure.
- 80% transmission at S-II line 672nm
- 6.5nm bandwidth for S-II
- Multi-layers anti-reflection coating
- Precise and sharp roll-off at off-band
- Infrared cut-off at 700-1100 nm
- 2 mm filter thickness
- Made on Schott substrate
- Finely polished to 1/4 wave accuracy
- Surface quality: 60/40 (MIL-O-13830 standard)
- Monochrome CCD/CMOS camera
- Deep sky narrowband imaging
Available in sizes
- 1.25" (26mm clear aperture)
- 36mm round unmounted
- 2" (45mm clear aperture)
- Multi layers anti-reflection coating
- Non cementing optical substrate coating
- Electron-beam gun evaporation with ion-assisted deposition coating technology to enhance coating durability and resistance to scratching as well as stability on central wavelength such that passband does not deviate with temperature change
- Planetary rotation system offers high precision and homogeneity of coating surface ensuring high value on passband transmission and off-band blocking.
Filter cell technologies
- CNC machined with aerospace grade aluminium
- Black anoidised finish and extinction treatment to prevent refection
- Laser engraved fade-free wordings
We care about delivering your filter in perfect form and thus every Optolong filter sits on a high density sponge carton lining and packaged in highly rigid plastic PP case with high pressure EVA case lining.
- What does the CCD suffix mean?
UV/IR coating is coated on top of the narrowband coating such that IR emissions from stars won't give you bloated stars.
Optolong is a brand dedicated for astronomical filters R&D and production under Kunming Yulong Optical & Electronics Technology Co. Ltd. Yulong is a professional manufacturer of high quality filters since 1999. Yulong has passed ISO9001 quality certifcation and all products meet ROHS standard authorised by SGS test.
Their major equipment include ultra clean room, five precise vacuum coating machines, Shimadzu UV-VIS-NIR spectrophotometer, 12 sinks ultrasonic cleaning machines and grinding/rolling/cutting machines.
Optolong filters only use the best glass — German's Schott glass as the substrate which has an industry leading level of flatness which is crucial to minimise the occurence of halo and ensure high quality image.