Optolong 3nm SHO narrowband filters set is for astrophotographers who want to obtain the maximum contrast of nebulae while cutting out background emission and suppressing star lights. This filter set includes a 3nm hydrogen-alpha filter and 3nm sulphur-II & oxygen-III filters. These filters cover the major emission lines of emission type nebulae. These filters are 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.

Highlights

• 85% transmission at O-III line 500.7nm, H-alpha line 656nm, S-II line 672nm
• 3nm bandwidth for H-alpha, O-III and 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)

Recommended applications

• Monochrome CCD/CMOS camera
• Deep sky narrowband imaging

Available in size

• 36mm round unmounted
• 2" (45mm clear aperture)

Coating technologies

• 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. 

User gallery

NGC6960 Veil Nebula Author: Andrea Maggi Telescope: Artec 200 Camera: ZWO ASI 294M Filters: Optolong RGB, 3nm HA & O-III Mount: 10 Micron 1000 HPS 60 Light RED 300 sec 60 Light GREEN 300 sec 60 Light BLUE 300 sec 36 light HA 600 sec 36 light OIII 600 sec

Rosette Nebula  Author: Andrea Maggi Camera: 071C, 1600MM, 2600MC Optics: Sharpstar 76EDPH Filter: Optolong 3nm SHO + L-Pro + L-enhance 58 Light 300 sec L-PRO 70 Light 600 sec L-eNhance 20 Light 600 sec HA 20 Light 600 sec OIII 20 Light 600 sec SII

North American Nebula and Pelican Nebula (HOO) Author: Tommaso Stella Camera: QHY168C Optics: Takahashi FS-60CB Filter: Optolong 3nm Ha 3nm OIII Exposure: 12 Light 900s HA 20 Light 600s O-III

About Optolong

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.