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

Optolong Dual-Band L-eXtreme Filter

£179.00✓ 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.

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''

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