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Optolong L-Pro Light Pollution Filter

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Optolong L-Pro (L-Professional) is a multi-bandpass filter which selectively suppresses the transmission of light pollution lines. For example, mercury vapor lamps, high and low pressure sodium vapor lights and skyglow caused by emission from neutral oxygen in our atmosphere.  The L-Pro works well for galaxies, reflection and emission nebulae and all other emission or reflection targets in combination with strong light pollution rejection.  This filter is Optolong's strongest light pollution filter that isn't a narrowband filter (such as the L-eNhance or L-eXtreme).

L-Pro enhances the transmission of major emissions from nebula while offering great color balance with its wide yet effective light pollution cutting transmission band. The balanced transmission allows objects with wide emission spectrum such as galaxies to be imaged with minimal color cast (easier to correct in post-processing). Among the emission lines enhanced are OIII (496, 500nm), H-beta (486nm), NII (654, 658nm), H-alpha (656nm) and SII (672nm).  Available in 2", 1.25" and selected DSLR camera sizes.

The Optolong L-Pro filters (apart from the 2-sided 10mm thickness version) have threads on one side to keep them very thin - 1.85mm - they can be used with Filter WheelsFilter Drawer System, focusers with a place to thread focal reducers internally (such as some Moonlite focusers) and camera nose pieces that fit into compression rings, but the 1.85mm filter should not be threaded into the imaging train like an adapter ring with threads on both sides.  The 10mm version with threads on both sides however can be used like an adapter ring and can be threaded directly into your optical train.  The back focus used by the 10mm version and clearance required is 7.6mm.


90% transmission at major nebula emission lines
Multi-layers anti-reflection coating
Precise and sharp roll-off at light pollutant lines
2 mm filter thickness (1.25", 2" and 77mm) | 1mm (clip series)
Made on Schott substrate
Finely polished to 1/4 wave accuracy
Surface quality: 60/40 (MIL-O-13830 standard)

Best Uses

Monochrome & one-shot-color CCD/CMOS camera
Deep sky color imaging, particularly reflective nebula and galaxies

Canon EOS FF Available for: EOS 5D/5DmarkII/III and 6D only

Nikon FF Available for: D600/D610/D700/D750/D800/D800E/D810/D810A/DF

Sony FF Available for: A7M/A7M2/A7M3/A7R/A7R2/A7R3/A7S/A7S2/A9


Returns Policy

You may return most new, unopened items within 30 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).

Items that have been opened, damaged or are otherwise unsaleable will be subject to a minimum 10% restocking fee, to be assessed by Telescopes Canada upon receipt of the returned goods

You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).

If you need to return an item, simply login to your account, view the order using the 'Complete Orders' link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.


We can ship to virtually any address in the world. Note that there are restrictions on some products, and some products cannot be shipped to international destinations.

When you place an order, we will estimate shipping and delivery dates for you based on the availability of your items and the shipping options you choose. Depending on the shipping provider you choose, shipping date estimates may appear on the shipping quotes page.

Please also note that the shipping rates for many items we sell are weight-based. The weight of any such item can be found on its detail page. To reflect the policies of the shipping companies we use, all weights will be rounded up to the next full pound.

Typographical Errors and Order Cancellations

Telescopes Canada reserves the right to cancel an order due to an error in pricing by Telescopes Canada or one of our suppliers, equipment being no longer obtainable, or other events which are out of our control.

Client-Initiated Cancellations

Client-initiated order cancellations are accepted prior to delivery of the equipment to the customer, thereafter it is a return.
Tpeak: T>90%
Spectrum: 380-750nm
Optical Density:  Light pollution emission is blocked 90%
Surface Quality: 60/40
Transmitted Wavefront RMS: λ/4
Parallelism (arcsec): 30s

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