The Optolong L-Pro (L-Professional) filter is designed to provide maximum luminosity of the spectrum other than those areas caused by light pollution...

It improves the visibility of various deep sky objects by selectively reducing the transmission of wavelengths of light pollutants, specifically those produced by artificial lightings including mercury vapor lamps, both high & low pressure sodium vapor lights and the unwanted natural light caused by neutral oxygen emission in our atmosphere (i.e. skyglow). As this filter is highly transparent in main nebula emission lines at  OIII (496nm and 500nm), H-beta (486nm), NII (654nm and 658nm), H-alpha (656nm) as well as SII (672nm), the filter is suitable for enhancing the contrast and details for both visual and photograghic purpose at sub-rural area with heavy  light pollution.
Unlike other light pollution filter UHC and CLS, L-Pro is multi-bandpass filter which offers better color balance by maximizing the transmission band. The balanced transmission allows astro photos to be taken with minimal color cast to broadband emission objects such as galaxies, reflection nebulae and globular star clusters. L-Pro is the best choice for light pollution suppression.

By providing maximum luminosity it reduces exposure time that is an important factor in deep sky imaging.

Images are for demonstration only. Camera is not included. Similar product might be shown on some images.

Main Use and Performance

Suitable for visual observation and astrophotography. The optolong L-Pro filter has a very low transmission reduction rate against continuous spectrum space objects, and thus is quite effective in suppressing light pollution sources when shooting galaxies, reflection nebulae and globular star clusters. The same holds true for visual star observations. The L-Pro filter alone can suppress infrared wavelength, and thus can be used at ease for “L” (luminosity) image shootings with CCD cameras. Please note that light pollution filters do not completely eliminate the effects of light pollution and definitely do not increase the object’s brightness, however they increase the contrast between nebula and night sky by making the background darker.

WARNING:

Optolong filters are not designed for solar observation. DO NOT LOOK AT THE SUN WITH ANY OPTOLONG FILTER as permanent eye damage will be the result.

Technical Data

• Schott substrate material
• Glass thickness 2.0 mm (1.25”/2”/77mm)  and 1.0 mm (Clip series)
• Surface Quality: 60/40 (Refer to MIL-O-13830)
• Fine-optically polished to ensure accurate 1/4 wavefront and < 30 seconds parallelism over both surfaces
• 90% transmission of main nebula emission lines (i.e. Ha 656nm, OIII 496nm & 500nm, SII 672nm and H-beta 486nm).
• Precision transmission of off-band, specifically the major emission lines of artificial light pollution (i.e. Na 589nm, Hg 435nm and 578nm).

Filter Cell

• Ultra-thin filter cell minimise vignetting by maximising possible clear aperture (clear aperture is 26mm for 1.25” size and 45mm for 2” size)
• Aero metal Material
• Precise CNC Machining
• Sand Blasting Process
• Black Anodized Finish
• Extinction Treatment to Prevent Reflection
• Laser Engraving No Fading

Available Sizes

• Standard 1.25” & 2”
• Round 77mm Unmounted
• Clip Filter Series (RESTRICTED TO GERMANY! Please do not order Optolong Clip filters from Germany. We can sell only Astronomik EOS Clip filters to Germany.)

Compatibility for Canon

Canon 450D Rebel XSi Yes
Canon Digital Rebel XS (digital) Yes
Canon Digital Rebel XSi Yes
Canon EOS 1000D Yes
Canon EOS 450D No
Canon EOS 500D Yes
Canon EOS Kiss F Yes
Canon EOS Kiss X2 Yes
Canon EOS Kiss X3 Yes
Canon EOS Rebel T1i Yes
Canon EOS 6D Yes
Canon EOS 60D + 60Da Yes
Canon EOS 7D Yes
Canon EOS 70D Yes
Canon EOS 50D Yes
Canon EOS 650D Yes
Canon EOS 600D Yes
Canon EOS 550D. Yes
Canon EOS 700D, Yes
Canon EOS 1100D Yes
Canon EOS 1200D Yes
Canon EOS 40D Yes
Canon EOS 30D Yes
Canon EOS 20D Yes
Canon EOS 10D Yes
Canon EOS D60 Yes
Canon EOS D30 Yes

Sony

A7M / A7M2 / A7M3

A7R / A7R2 / A7R3

A7S / A7S2

A9

Nikon Full Frame

This filter is compatible with the following FULL FRAME Nikon cameras: D600 / D610 / D700 / D750 / D800 / D800E / D810 / D810A / DF

Applicable camera body

This filter is compatible with Canon EOS R/Ra, RP, R5 and R6 cameras

Applicable Lenses

Full range of RF main and auxiliary lens

Full range of EF main and auxiliary lens (adapter is required）

Packaging

• Plastic PP Case
• Imported High Pressure EVA Case Lining
• Silver Cardboard Box
• High Density Sponge Carton Lining

Optical Coating

• Multi-layer 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. (Please note, "planetary rotation system" is a type of optical coating process and does not refer to the astronomical system describing the motion of the planets in our solar system.)

The Major Emission Lines of Nebulae: H-α 656.3nm, H-β486.1nm, OIII 495.9nm, OIII 500.7nm 
The Major Emission Lines of Artificial Light Pollution: Hg 435.8nm, 546.1nm, 577nm, 578.1nm, Na 598nm, 589.6nm, 615.4nm, 616.1nm