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Optolong L-eXtreme Dual-band Filter - 2-inch

SKU : OL-L-EXTREME-2

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  • Dual-band light pollution filter - 2-inch.
  • The L-eXtreme filter is dual-band that passes H-alpha and O-iii emission lines.
  • It isolates these two nebula emission lines so that the contrast and signal-to-noise ratio between nebulae were maximized.
  • These two elements (Hydrogen and Oxygen) factor greatly in the scientific exploration of life.

Product Details

  • Dual-band light pollution filter - 2-inch

    The advantage of the L-eXtreme filter is that there is no transmission between the H-beta and OIII lines and there are also no nebula emission lines there. In this case, it isn't letting light pollution come through so it maximizes nebula signals and the sky background is made darker while imaging.

    The L-eXtreme filter should better isolate the emission lines and better protect from light pollution.

    L-eXtreme Introduction

    Optolong L-eXtreme is a two 7 nm bandpass filter which can be used with one-shot color 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 nebula, even in bright, light pollution skies. Optolong believes the design of L-eXtreme filter would be a better choice for fast systems at a 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 maximized. For people who are living in very light-polluted areas, or when the moon is out, the L-eXtreme will be a good filter.

    Unlike the L-eNhance filter which is a tri-band (transmits H-b, H-a, and O-iii), the L-eXtreme filter is dual-band that passes H-a and O-iii emission lines.

    Comparison of transmission lines of L-eXtreme, L-eNhance, and L-Pro:

    Optolong L-eXtreme Dual-band Filter - 2-inch-transmission-01

    Optolong L-eXtreme Dual-band Filter - 2-inch-transmission-02

    Optolong L-eXtreme Dual-band Filter - 2-inch-transmission-03

    You can also view this charts in greater detail in the Gallery tab, click on the thumbnails for each image.

    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 for the exploration of life.

    Therefore, Optolong highlights H-a, H-b, O-iii, and O-ii, and reduce the signal of sulfur.

    Spectrum and Characteristic

    • Substrate: B270.
    • Thickness: 1.85 mm.
    • FWHM: O37 nm+Ha 7 nm.
    • Blocking range: 300 to 1000 nm.
    • Blocking depth: light pollution line blocking >99%.
    • Surface quality: 60/40.
    • Transmitted Wavefront RMS: λ/4.
    • Parallelism: 30s.

     

  • specifications

    BandpassMulti Bandpass
    Filter ShapeRound
    Filter Size2"
    Filter Thickness1.85 mm
    Filter TypeDual Band
    Filter TypeLight Pollution/City Light Suppression
    Free ShippingYes
  • included items

    • Dual-band light pollution filter - 2-inch.
    • The L-eXtreme filter is dual-band that passes H-alpha and O-iii emission lines.
    • It isolates these two nebula emission lines so that the contrast and signal-to-noise ratio between nebulae were maximized.
    • These two elements (Hydrogen and Oxygen) factor greatly in the scientific exploration of life.

Product Reviews

Customer Reviews
4.9 Based on 7 Reviews
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Filter Reviews:
RS
01/01/2021
Robert S.
United States United States
I like this filter

Awesome for light pollution and full moon imaging of emission nebulas.

RM
11/17/2020
Richard M.
United States United States
Outstanding service

Did not use it was Purchased as a gift. I am sure he will love it

A
11/17/2020
Anonymous
United States United States
How to **** Light Pollution in a Bortel 8 Zone

This filter has made my life. Using a DSLR is tough especially , long exposures with intense light pollution. I used to manage a 30 sec to 1 minute exposure if I was luck and take 200 - 400 subs. With the L-Enhanced filter I get 5 - 7 minute exposures without the pollution with get ISO levels. It has been worth every penny and more. Unmodified Nikon D7500 DSLR with ISO 1250, 6 min exposures and 80 subs using a 250mm telescope; the picture was processed with only 3 levels adjustments (Stretches) and a1 curves adjustment. A picture is worth a thousand words!

DB
11/17/2020
David B.
United States United States
Excellent filter

With My one-shot color camera I have been getting the color I want in Class 4 Bortle skys.

OPT Telescopes Optolong L-eXtreme Dual-band Filter - 2-inch Review
A
11/17/2020
Anonymous
United States United States
This is not an ideal filter for fast systems, but great for slower ones

I originally purchased this filter for use with my ASI533MC Pro OSC, primarily on the RASA-8 and on an F4 newtonian. In large part, this was based on the specifications stating "Optolong believes the design of L-eXtreme filter would be a better choice for fast systems at a competitive price". In fact, while the Oiii performance at F2 and F4 is good, the Ha band is already attenuated at F4 and is markedly so at F2. Oiii predominates progressively with decreasing F-ratio. On a predominantly Ha object, exposure times with the F2 instrument are very similar to those on a F5.6 instrument of the same focal length for similar red levels, due to passband shift with increasing entry cone angles. In fact, the best pictures that I have had from this filter are with slower instruments. With those instruments, its performance is excellent.

OPT Telescopes Optolong L-eXtreme Dual-band Filter - 2-inch Review
NB
08/25/2020
Nicholas B.
United States United States
Great filter for the price, with a minor "issue"

Used this filter twice on emission nebulae from my light polluted area north of Detroit, amazing contrast even when the moon is near full! Almost no gradients from light pollution or moonglow which is surprising, very small stars but I wish I could give this 4.5 stars because I have noticed some small star halos on brighter stars in the star fields surrounding nebulae. Not a big issue to me but some may care about this more than I do. Great filter overall though, will continue to use this.