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Optolong L-eNhance Dual Narrowband Filter (H-Alpha and H-Beta/O-III)

14 In Stock - Ships Today if Ordered by 2pm! (Tues - Fri)

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The relentless spread of urbanization and its associated light pollution have become a growing problem for all amateurs and astro photographers. The current solutions to the problem can be expensive and frequently include the purchase of a monochrome camera, several types of narrowband filters and a filter wheel.

L-eNhance provides an economical and practical solution for amateurs. It is a dual band-pass narrowband filter which has been designed for DSLR (digital SLR), color CMOS and CCD Astrophotography Cameras. The convenience and cost effectiveness of this filter allows amateurs to image a rich selection of astronomical images, even in bright, heavily light-polluted areas. This filter is excellent for imaging object which emit H-alpha and O-III/H-beta light with near-complete rejection of all other light.  For more broadband targets such as galaxies and reflection nebulae, the Optolong L-Pro is the best-suited Optolong filter.

Optolong believes the design of the L-eNhance filter is a technical innovation among filters. It effectively isolates the H-Alpha (10nm band width), H-Beta, and Oxygen III (24nm band width) nebula emission lines and achieves a maximum transmission of up to 90%. The performance of this filter delivers images that superbly control the impact from light polluted skies.  This filter is excellent for emission targets such as nebulae which emit in H-Alpha and Beta, and O-III.  For more broadband targets such as galaxies or reflection nebulae, the L-Pro is excellent.  For maximum light pollution rejection with 7nm bands at H-Alpha and O-III, try the L-Extreme filter.

The Optolong L-eNhance filters (apart from the 2-sided 10mm thickness version) have threads on one side to keep them very thin - 1.85mm not including the threads - they can be used with Filter Wheels, Filter 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 10mm version has a thickness of 7.6mm not including the threads.

L-eNhance Filter Spectrum Curve

According to the characteristics of celestial body emission lines and feature of light pollution span of spectrum, Optolong specially designed and optimized dual-band L-eNhance filter in order to retain the prominent color of nebula RGB while blocking out most of light pollution.

Canon EOS-C Supported Models:

7D2/80D/800D/77D/70D/760D/750D/700D 650D/600D/550D/500D/400D/100D/1100D 1200D/1300D

The filters work with all EF lenses, but is not suitable for Canon EF-S lenses.

More details from Optolong can be found Here

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.
Substrate: B270
Thickness: 1.85mm
Tpeak: T>90%
Blocking range: 300-1000nm
Blocking depth: light pollution  line blocking >99%
Surface quality: 60/40
Transmitted Wavefront RMS: λ/4
Parallelism (arcsec):

Questions & Answers

  • Will the 2 inch double theaded version also fit into the ZWO 7x2 filter wheel?

    Unfortunately the double-threaded filters are very slightly too thick and will rub against the casing of the electronic filter housings

  • What is the difference between the 2" L Enhance filter and the two sided threaded?

    The difference between the 1 and 2-sided threads are that the 2-sided threads allow you to install a filter directly into the imaging train just like a spacing or extension ring, so you don't need anything else like a filter wheel or drawer to use it.

    One downside is that it's a little more work to remove it if needed.

    The 2-sided ones have a larger stronger metal ring around the filter and as such they don't generally fit into filter wheels or filter drawers.  They do work directly in the imaging train, and generally are Ok inside flatteners and other places where clearance isn't too tight.  You will need about 8mm clearance, not including threads.

    In most cases the normal 1-sided ones are best to buy as they're more flexible, but the 2-sided ones are good for a lost cost solution installing a filter that you intend to leave in the light train long term.

  • Can this filter be mounted while using the WO 6AIII 2" reducer/flattener?

    Yes you can mount the 2" filter inside the flattener