Why do we make a L-Para filter with a dual band of 10nm?

In Chinese culture, the number ten symbolizes perfection in every way. An idiom in Chinese, 'shi quan shi mei' epitomizes reaching the best and most ideal state. Therefore, we aspire for the L-Para filter to achieve this standard. Specifically, it operates in dual bands, each with a width of 10nm. The repetition of the number ten signifies double wishes for your photography experiences and clear skies always. 

During the research phase, L-Para is dedicated to optimizing halo performance and effectively blocking out light pollution emissions.

Images captured by L-Para will exhibit a dark background and precise colors. Halos around bright stars are caused by a complex optical chain. 

While we can't say no halo, but we believe that L-Para offers a entirely new perspective. 

Additionally, L-Para is compatible with both fast optics and normal optics, covering focal ratios from F2 and above. One filter is designed to work with all your telescopes. L-Para, bringing you greater efficiency.

1.  Optolong L-Para(L-Parallels)

Optolong L-Para is a brand new dual narrowband 10nm light pollution filter. The FWHM of L-Para is 10nm for OIII (500.7nm) and H-Alpha (656.3nm) respectively. The transmittance of nebulae emission lines at are both greater than 85% in system with focal ratios of F2 and above. It effectively filters out mercury lamp, sodium lamp, and LED light pollution emission lines. At the same time, it has excellent contrast and anti-halo characteristics, allowing you to capture detailed and vivid nebula images. L-Para is suitable for both normal optical systems and fast optical systems, such as RASA and Hyperstar systems. Even when light is incident at an oblique angle, it can still maintain high transmission rates to provide you with a clear and precise shooting experience.

Key Features:

Broad Compatibility:

A dual narrowband filter suitable for all telescope systems, adaptable to fast optics (focal ratios of F2, F2.8, F3.2, F4) as well as various standard/normal focal ratio telescopes.

Light Pollution Resistance:

Effectively cuts off emission lines from mercury lamps, sodium lamps, LEDs, and other light pollution sources, making it applicable to Bortle Scale1- 7 dark skies.

High Transmission Rate:

In systems with a focal ratio of F2 and above, the transmittance of nebula emission lines OIII and Ha exceed 85%, resulting in higher imaging efficiency.

Excellent Contrast:

The high transmittance of nebula emission lines (OIII & Ha) combined with deep cut-off of light pollution bands significantly improves image contrast and detail richness.

Anti-Halo Characteristics:

The design has undergone several round of optimizations and many times of repeated testing ,resulting in a marked improvement in anti-halo performance, enhancing the capture of bright stars.

2.Spectrum

According to the characteristics of the emission lines of celestial bodies and light pollution, as well as the characteristicas of the normal telescope and fast ratio imaging system, L-Para has been maintaining high transmittance at OIII and Ha while blocking light pollution emission lines.

How to read the chart?

▲The horizontal axis is the Wavelength in Nanometers(nm).

▲The vertical axis is transmission in %.

3. Coating Technology

·Multi-layers anti-reflection coating

·Non-cementing optical substrate coating

·Optolong filter adopts precision coating based on Ion-assisted deposition coating technology for durability and resistance to scratching, as well as stability on CWL(central wavelength) no deviation affected by temperature change.

·Planetary rotation system offers precision and homogeneity of coatings ensuring high value on transmission of pass-band and Optical density of off-band.

4. L-Para(L-Parallels) Gloable Price

5. Packing

Outer Box: silve box

Plastic Box: PP material

Lining: imported high pressure white EVA material

6. L-Para Filter Performance

I. Halo Testing

NGC 7000/Star level 1.24

68mm F3.9+ASI 6200MC、Single300s

II. Halo Testing 

IC 434 The Horse Head Nebulae /1.74 level

68mm F3.9+ASI 6200MC、Single 300s

III. Heart Nebula

Sharpstar 76+2600MC + Optolong L-Para

Credit: Andrea Maggi

IV. Valle degli Ulivi 

Lights: 38x600s Apo 102/570mm + ASI 2600mc + AZEQ6 GT+ Optolong L-Para

Credit: Tommaso Massimo Stella

2"（M48×0.75）