Optolong SHO Narrowband Deep Sky Imaging Filters

£419.00✓ 2 year warranty

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1.25" Mounted: £359.00
2" Mounted: £559.00
31mm Round Unmounted: £419.00
36mm Round Unmounted: £429.00

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Optolong LRGB Deep Sky Imaging Filters

Special Bundle Price - Save 10%!

Buy a Optolong LRGB and SHO filter set together to save 10%

Simply add both filter sets to your basket to automatically receive the discount.

About this product

Model: opt_sho_31mm

Latest Version - Higher contrast and coating enhancements.

Narrowband filter set including SII (S) 6.5nm, Ha (H) 7nm and OIII (O) 6.5nm 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.

Warning - Optolong filters are not designed to be used for solar observation. Do not look at the sun through this filter as it will cause permanent eye damage.

FEATURES

80% transmission at passband / Precision off-band blocking
Infrared wavelength 700-1100nm 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
1.25" / 2" mounted or 31mm / 36mm unmounted sizes.
Supplied in a protective plastic case with EVA foam lining
2mm Thick Schott Glass
Fine-optically polished on both sides - ensures accurate λ/4 wavefront and <30 seconds parallelism over the both surfaces

Transmission Chart

Red Line: H-alpha, 7nm centred at 656.3nm.

Blue Line: SII, 6.5nm centred at 671.6nm.

Green Line: OIII, 6.5nm centred at 500.7nm

Technical Data

Schott substrate material
Thickness 2.0 mm
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
95% transmission at passband
Infrared wavelength 700-1100nm 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