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Optolong L-Pro 2″ Filter

Optolong L-Pro 2″ Filter

£145.00

The Optolong L-Pro 2″ filter is designed to provide maximum transmission of the spectrum, except in those areas affected by light pollution.

This listing is for the 2″ filter and price includes UK delivery.

Description

The Optolong L-Pro (L-Professional) 2″ filter is designed to provide maximum luminosity of the spectrum other than those areas caused by light pollution…

It improves the visibility of various deepsky 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 astrophotos 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.

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).
  • Pricision 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 minimises vignetting by maximising clear aperture (clear aperture is 45mm)
  • Aerometal 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.)

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

 

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UK Delivery Prices include postage to all mainland UK addresses, except where indicated. Larger items may attract a surcharge for off shore or remote locations. When your item is dispatched, you will receive an email from our shopping cart saying ‘Your order is complete’ We use Royal Mail and Courier services, whichever is more appropriate for the weight and value of your order. International Delivery: Website prices DO NOT include International delivery costs unless specified. We are happy to ship to most countries. We use a variety of Royal Mail and Courier services, depending on the weight, size, value and urgency of your order. Place your order via the shopping cart and you will be advised by email of additional shipping charges prior to the processing and dispatch of your order. Or simply email us for details of shipping charges to your country before you place your order. Some items which are particularly popular with overseas purchasers already display, in the purchase menu, combined purchase and shipping costs to various regions adjusted for UK VAT (sales tax) where necessary. If you reside outside the European Union, please check with your customs authorities for details of any import taxes, duties and other charges that may be imposed on entry to your country. We have no control over these.