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What is the L2 Dual-Combo Set?
L2 Dual-Combo Set includes two premium filters: one L-eXtreme and one L-Synergy.
**Already have a 2" L-eXtreme? Get just the L-Synergy HERE.
L-eXtreme: The L-eXtreme is a dual-narrowband filter (7nm) designed to exclusively transmit the key nebula emission lines of OIII (500.7nm) and Hα (656.3nm).
L-Synergy: The L-Synergy is a dual-narrowband filter (7nm) that provides high transmission for both the SII (672.4nm) and OIII (500.7nm) spectral lines.
What is the L2 Dual-Combo Set?
The L2 Dual-Combo Set is engineered to unleash the power of the Hubble Palette (also known as "SHO" imaging) for color camera users, supporting telescope systems as fast as F3.3 and above (i.e., slower systems).
Tailored specifically for astrophotographers with one-shot color cameras, this set includes two premium filters: OIII & Hα (L-eXtreme), OIII & SII (L-Synergy).
This innovative combination breaks through the traditional limitations of shooting one-shot color cameras with narrowband imaging. With just two filters, users can achieve stunning Hubble Palette images at a fraction of the cost and complexity of more traditional, three-filter approaches using monochrome cameras.
The L2 Dual-Combo Set captures the distinct colors of nebulae radiating in OIII, Hα, and SII light, while filtering out the vast majority of light pollution. Its transmission profile is as follows:

How to read the chart?
▲The horizontal axis is the Wavelength in Nanometers(nm).
▲The vertical axis is transmission in %.

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.
·Precision and homogeneity of coatings ensuring high transmission of desired passbands, and efficient removal of other, unwanted, colors.
Specifications
|
Subustrate |
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'' |
Package
- Plastic PP Case
- Imported High Pressure EVA Case Lining
- Silver Cardboard Box
- High Density Sponge Carton Lining
Sizes
- Standard 2”




