Optolong 3nm SHO Ultra Narrow Band Filters

Optolong 3nm SHO Ultra Narrow Band Filters

£329.00✓ 2 year warranty

Product description
FAQ

:	1x in stock shipped 1-2 working days

Ask a Question Ask a Wishlist

Add To Wishlist

Send To Friend

About this product

Model: optolong_sho_3nm_ha36

New 3nm Ultra Narrowband Astronomy Filters from Optolong

Narrowband filter set including SII (S) 3nm, Ha (H) 3nm and OIII (O) 3nm 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.

H-Alpha 3nm Filter: The most popular narrowband filter allowing 3nm bandwidth of light centred on a wavelength of 656nm to pass through. Low transmission of other wavelengths of light specifically those produced by artificial light including mercury vapour, both high and low pressure vapour lights and unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e.skyglow). Great choice for higher contrast and revealing subtle nebula details.

OII 3nm Filter: Designed for observing / imaging nebulae allowing 3nm bandwidth of light to pass centred on a wavelength of 500nm which corresponds to the OIII emission line. Low transmission of other wavelengths of light, specifically those produced by artificial light including mercury vapour, both high and low pressure sodium vapour lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow). OIII emits at 495.9nm and 500.7nm which represents a blue-green colour. Many images of planetary nebula and supernovae remnants are taken with only H-Alpha and OIIII filters. They show great structural details with natural colours, similar to an RGB image.

SII 3nm Filter: Designed for observing / imaging nebulae allowing 3nm bandwidth of light to pass centred on a wavelength of 672nm. Low transmission of other wavelengths of light, specifically those produced by artificial light including mercury vapour, both high and low pressure sodium vapour lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow).

IMPORTANT: Filters manufactured by Optolong are NOT designed for observing or photographing the Sun. DO NOT use Optolong filters to observe or photograph the Sun. If you do it will result in permanent eye damage!

FEATURES

85%+ transmission at passband / Precision off-band blocking
Infrared wavelength 700-1000nm 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
2" mounted or 36mm unmounted sizes.
Supplied in a protective plastic case with EVA foam lining
Optical Glass 2mm thick in 36mm filters, 1.85mm in 2" filters.
Fine-optically polished on both sides - ensures accurate λ/4 wavefront and <30 seconds parallelism over the both surfaces

Transmission Chart

SII Line: H-alpha, 3nm centred at 656nm.

Green Line: SII, 3nm centred at 672nm.

Blue Line: OIII, 3nm centred at 500nm

Technical Data

Schott substrate material
Thickness 2.0 mm in 36mm filters, 1.85mm in 2" filters.
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
85%+ transmission at passband
Infrared wavelength 700-1000nm 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