Optolong Dual-Band L-eXtreme Filter
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Optolong Dual-Band L-eXtreme Filter

£169.00
  (25 Reviews)
✓ 2 year warranty
  

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About this product

Model:  opt_l-extreme_1.25
Part Number:  13801

New L-eXtreme Filters - Dual H-alpha / Oxygen III 7nm Narrowband Filter

For One Shot Colour / DSLR Imaging - Simultaneously Capture H-alpha and Oxygen III

The advantage of the L-eXtreme filter is that there is no transmission between the H-beta and OIII lines, as there is no nebula emission lines there. In this case, it isn't letting light pollution come through so that maximises nebulae signal and make the sky background darker while imaging. The L-eXtreme filter should better isolate the emission lines only and better protect from light pollution.

Unlike the Optolong L-eNhance filter which is a tri-band (transmits Hb, Ha, and OIII), the L-eXtreme filter is dual band that passes Ha and OIII emission lines.

IMPORTANT: Filters manufactured by Optolong are NOT designed for observing or photographing the Sun. DO NOT use Optolong filters to observe or photograph the Sun. If you do it will result in permanent eye damage! 

FEATURES

  • High transmission of H-Alpha and Oxygen III emission lines (avg. 90% or higher)
  • FWHM: Ha 7nm, OIII 7nm
  • Use with colour DSLR, CMOS and CCD Cameras
  • 1.25" or 2" Mounted Filters.
  • Supplied in a protective plastic case with EVA foam lining
  • B270 1.85mm Thick Glass
  • Fine-optically polished on both sides - ensures accurate λ/4 wavefront and <30 seconds parallelism over the both surfaces
  • Ultrasonic wave cleaned substrate with purified water - Cleanup by 13 stage purified water tank to remove impurities and dust effectively
  • Ion source assisted coating— For durability and resistance to scratching, as well as stability on CWL (central wavelength)  - no deviation affected by temperature change
  • Stringent quality testing process - each filter is tested on a spectrophotometer and laser interferometer

Introduction

L-eXtreme is a two 7nm bandpass filter which can be used with one-shot colour cameras like DSLR's (digital SLR), and monochrome CCD cameras, it is also more suited for fast systems. The convenience and cost effectiveness of this filter allows amateurs to image a rich emission nebulas, even in bright, light pollution skies. Optolong believes the design of L-eXtreme filter would be better choice for fast systems in competitive price. It isolates the H-Alpha, and Oxygen III nebula emission lines so that the contrast and signal-to-noise ratio between nebulae were maximised. For people who is living in very light polluted areas, or when the moon is out, the L-eXtreme will be a good filter.

Hydrogen is the largest, the most primitive, the simplest, and the oldest element in the universe. Scientists consider that Hydrogen amounts to more than 90% of visible substance in space. Our sun is 5 billion years old, but so far hydrogen is still the key matter of nuclear fusion. While the Sulfur element does not have much scientific significance, so keeping H and O is meaning for exploration of life.

Transmission Chart

White Line - Represents the transmission curve of the L-eXtreme Filter.

The Major Emission Lines of Nebulae: H-α (656.3nm), H-β (486.1nm), OIII (495.9nm) and OIII (500.7nm)

The Major Emission Lines of Artificial Light Pollution: Hg / Mercury (435.8nm, 546.1nm, 577nm and 578.1nm), Na / Sodium (598nm, 589.6nm, 615.4nm and 616.1nm)

Sample Images

  • Object: M42
  • Time : 15th.--16th. March 2020
  • Place: HongKong-Shatin
  • Camera : ZWO ASI183MC Pro
  • Telescope : f/5 @ Sky-Watcher N130/650 w coma corrector
  • Filter : Optolong  L-eXtreme 2"
  • Mount : iOptron CEM25EC
  • Guide : 120mm mini guide scope, ZWO ASI120MM mini
  • Light pollution level 7~8（City center, light pollution disaster area）
  • Copyright: ©Vincent Cheng (Hong Kong)

 

  • Object：NGC6946, Barnard 150 & Sh2-129 Flying Bat nebula
  • Equipment：Canon 6D mod+WO SpaceCat 51+Optolong L-eXtreme&L-Pro
  • Data：RGB 25 x 600" ISO 3200 - Optolong L-Pro
  • H-Alpha & OIII 20 x 1500" ISO 320 0 - Optolong L-eXtreme
  • Copyright: ©José Jiménez (Spain)

What's in the box

  • L-eXtreme Filter
  • Silver Cardboard Box
  • Plastic PP Box
  • High Pressure EVA case lining

Specifications

Substrate

B270

Thickness

1.85mm

FWHM

O3 7nm+Ha 7nm

Blocking range

300-1000nm

Blocking depth

Light pollution  lines blocked >99.9%

Surface quality

60/40

Transmitted Wavefront RMS

λ/4

Parallelism

30''

Customer reviews

Average Rating (25 Reviews):  
Write a Review and share your opinions!
Rating (max 5):  
Optolong L-eXtreme Filter
Friday, 28 January 2022  | 

For me, in terms of detail captured, this is an absolute game changer. I couldn't work out 'correct' exposure times and gain settings, so my first light with this filter was guess work. Even so, with just a few subs I could see more detail in the Elephant's Trunk Nebula than I had ever managed to capture before, even with hours of data. I have a lot to learn in regard to processing the data produced by this filter but already this feels like a massive leap forward on my AP journey.

Rating (max 5):  
Amazing
Thursday, 18 November 2021  | 

This is just an amazing piece of filter. We are using it bortle 9 sky.

Rating (max 5):  
I don't even know what I'm doing, and this came out of Bortle 8 Dartford skies.
Sunday, 26 September 2021  | 

https://stargazerslounge.com/uploads/monthly_2021_09/IC1396-Hubble-Signed.png.76a72ea1585628673fc597474b7f2cf5.png

Rating (max 5):  
Optolong L-Extreme - well worth the money!
Thursday, 23 September 2021  | 

Finally got the chance to try this filter on a DSO. I had previously imaged the Eastern Veil Nebula with Skywatcher 200P and Canon 1000D (modded), proding a reasonable image with 1.5 hrs of data. However, the image was dominated by the star field and there wasn't very much blue nebulosity (OIII emission). The Optolong L-Extreme improved this enormously, isolating the HA and OIII nebulosity beautifully and enhancing the nebula above the background star field. All on 1.5 hours (5 minute subs) exposure, with a full moon nearby! Very pleased with this filter.

Rating (max 5):  
Stunning Results
Thursday, 16 September 2021  | 

I already had the ZWO duo-band filter, but seeing other images taken with this filter, I took a punt on it to see how much of a difference this filter makes. I was absolutely blown away by the immense richness of the colours, with limited clear skies of late, I only had one night but imaged both the east veil nebula (C33 - NGC 6992) and the bubble nebula (C11 NGC7635) and the results were stunning, so looking forward to the coming dark skies season and have a list of objects to capture.

I am using this with the ZWO filter wheel and the ASI 533MC Pro, with William Optics Z73 APO

Rating (max 5):  
Game changer
Thursday, 29 July 2021  | 

I could not be more impressed! Revealed otherwise hidden details that my Astronomik pollution filter excluded. There were perhaps issues with focusing and platesolving but perhaps I need to up the exposure times a bit

Rating (max 5):  
Optolong Dual-Band L-eXtreme Filter
Thursday, 29 July 2021  | 

Haven't used the filter yet due to cloud cover, but fitted on my RedCat scope nicely. Usual great service from FLO, thanks!

Rating (max 5):  
Game Changing
Monday, 26 July 2021  | 

I only received this lens a few days ago & was lucky to have a whole night clear last night. I Took 50x180 sec on IC1396. Test shot at same exp length showed good Ha signal straight out of my asi 533. I'll be processing these later today but I expect good things. The lens acted faultlessly under a 97% Moon, VERY impressed.
Came well packaged & arrived very quickly from FLO as usual.

Rating (max 5):  
Incredible Contrast
Thursday, 22 July 2021  | 

I live in a Bortle 4/5 zone, with more light pollution towards the North, so wasn’t sure how much of a difference this would make for the summer nebulae (was primarily bought for the northern DSOs such as heart / soul men’s etc). However it is a game changer for everything. The signal and contrast from veil, butterfly, pelican nebulae were a step change improvement to equivalent images taken without it. Thoroughly recommend the L-extreme if you are after imaging the Ha O3 nebulae. Can’t wait to have a look at Orion ….. Service from FLO was as excellent as ever.

Rating (max 5):  
Great Filter
Friday, 21 May 2021  | 

Only managed to use the filter for one short session (2hours) and was blown away with Subs and final image. I live in Bortle class 5 and the moon was at approx 50%, all subs came out clear with lost of nebula details. Final image show no star bloating and lots of detail for so little data. Highly recommend the filter and FLO as they have been great with every purchase I have made.

Read all 25 customer reviews...

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