Optolong L-eXtreme Dual Narrowband Filter - 1.25"
Optolong L-eXtreme Dual Narrowband Filter - 1.25"
Optolong L-eXtreme Dual Narrowband Filter - 1.25"
Optolong L-eXtreme Dual Narrowband Filter - 1.25"
Optolong L-eXtreme Dual Narrowband Filter - 1.25"
Optolong L-eXtreme Dual Narrowband Filter - 1.25"
Optolong L-eXtreme Dual Narrowband Filter - 1.25"

Optolong L-eXtreme Dual Narrowband Filter - 1.25"


Regular price€249,00
(Including VAT)

The L-eXtreme Filter is perfect for deep sky nebula photography from the city as it uses much tighter narrowband limits - blocking out unwanted glow from the city. The relentless spread or urbanization and its associated light pollution have become a big problem for all amateur astro photographers around the world. One solution is to purchase a Mono camera but this can be expensive and might also require the purchase of several types of narrowband filters and a filter wheel.

These filters open up a whole new opportunity for fast newtonian telescopes, double-lens ED refractors or even achromats, allowing for extremely detailed and high class astronomical images even from heavy light polluted cities as it blocks out all artificial light pollution sources as it is a dual narrow bandpass filter, only allowing for the wavelengths of O-III and H-Alpha. This filter is fast bcoming a must have item for serious Astro-imagers using OSC cameras.

The L-eXtreme is a two 7NM narrow bandpass filter which can be used with one-shot color cameras like DSLRs (digital SLR), color CMOS and monochrome CCD cameras. The convenience and cost-effectiveness of this filter allows amateurs to photograph rich emission type nebulas, even in bright, heavily light-polluted skies. The L-eXtreme filter is the best choice for fast optical systems as it isolates the H-Alpha and Oxygen III nebula emission lines so that the contrast and signal-to-noise ratio between these are maximized.

L-eXtreme has a multiple anti-reflective coatings on the optical substrate. The L-eXtreme filter uses a precision coating based on ion deposition coating technology. This ensures durability and scratch resistance as well as stability on the CWL (central wavelength), which is not affected by temperature changes. Absolute precision of the coatings as well as maximum values for transmission in the passband and optical density in the off-band range are guaranteed for all filters.

IMPORTANT WARNING: These nebula filters are NOT designed for observation of the Sun. Do not use this filter to look at the Sun as serious eye damage, blindness as well as damage to equipment may result.

Filter Details:

  • Professional photographic filter for astronomy
  • Improves deep sky emission nebula photography
  • Best choice for extreme light pollution suppression
  • For taking pictures also from highly light-polluted areas
  • Dual-narrow-band filter with high transmission for O-III and H-Alpha lines
  • Does not require very large or extremely expensive telescopes
  • Excellent results also with fast inexpensive newtonian telescopes, double-lens ED refractors or even achromats
  • L-eXtreme filter is the better choice for fast systems at a competitive price
  • CMOS colour cameras can deliver an image quality that comes close to CCD monochrome cameras
  • Filter diameter: 1.25 inches / 31.7 mm
  • Connecting thread: M28x0.6mm
  • Selected optical glass material
  • Spectrum: 300-1000nm
  • Off-Band Blocking: > 99 %
  • Surface Quality: 60/40 (Refer to MIL-O-13830)
  • Fine-optically polished to ensure accurate 1/4 wavefront and highest parallelism over the both surfaces
  • High transmission at major nebula emission lines (i.e. H-alpha 656nm and OIII 496nm & 500nm)
Whats included:
  1. L-eXtreme filter (designed for 1.25" optics)
  2. Dust protection box
  3. Technical Data
Please Note: Items in stock and ready for dispatch immediately are usually delivered within 24-48hrs. Some items may be 'Special Order Items' and require additional lead time before being dispatched eg. 5 - 10 Working days - This will be highlighted on the product page before purchase.

All orders are shipped using our reputable courier partners to ensure your items arrive safely and promptly. While we do offer International Delivery, we are unable to ship large Telescopes and Mounts outside of Ireland.



Est. Delivery Time after Dispatch:
24 - 48 hrs

Standard Express Shipping:
Ireland Nationwide: from €9.95

Note: Larger telescopes which contain multiple boxes include an additional surcharge. Shipping is calculated automatically at the checkout.


You can also avail of our FREE 'Click & Collect' service at the checkout, where you can order online and collect from our head office. Depending on the items and availability, these can be ready for collection within a few hours.

"NOTE: Please wait until we let you know your order is ready before you arrive, to arrange a suitable time for collection."




Est. Delivery Time after Dispatch:
24 - 48 hrs

Standard Express Shipping:
Norther Ireland: from €19.50+

Additional Info:

Standard Express Shipping rate applies up to a max order weight of 30kg Nationwide. - Large heavy items from 30kg+ include an additional surcharge, depending on the overall weight.

Unfortunately due to Brexit we are currently unable to ship to Mainland UK at this time. 


Est. Delivery Time after Dispatch:
24 - 72 hrs

Standard Express Shipping:
European Union: from €18.95+

Shipping available for items up to a max order total weight or volumetric weight of 27kg.

Additional Info:

If your country is not listed below please contact us for more information.

Standard EU Delivery Regions:
Germany, France, Belgium, Poland, Luxumbourg, Netherlands, Sweden, Denmark, Portugal, Spain, Austria, Italy, Poland, Czech Republic, Croatia, Malta, Greece


Est. Delivery Time after Dispatch:
48 - 72 hrs

Standard Express Shipping:
US & Canada: from €28.50+

Shipping service available for items up to a max order total weight or volumetric weight of 20kg.

Additional Info:

 * Customs / Import duties may apply in these regions. For more information please contact your local tax/customs office.

: Its essential that when placing an order, you include a valid 'Contact Telephone Number' for the delivery address or for the person receiving the item. This is necessary to avoid potential delays or problems with your delivery.

Please Note: Delivery times listed above are estimated. These are calculated from when your order is Completed & Dispatched (not from when the order is placed) and times may also vary for some remote post codes. Delivery service takes place Mon-Fri (excl. Bank/Public Holidays).

Shipping Disclaimer: All of our parcels are sent via a 3rd party registered courier service to ensure safe and prompt delivery. While we endeavor to ensure that all parcels are delivered within the specified time frame, 'Horizon Astronomy' can not be held responsible for delays due to adverse weather conditions or other courier/technical related issues outside of our control.

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