- The Major Emission Lines of Nebulae
H-β486.1nm OIII 495.9nm OIII 500.7nm H-α656.3nm - The Major Emission Lines of Artificial Light Pollution
Hg 435.8nm 546.1nm 577nm 578.1nm
Na 598nm 589.6nm 615.4nm 616.1nm

- Schott substrate material
- Thickness 1.0 mm
- Surface Quality: 60/40 (Refer to MIL-O-13830)
- Fine-optically polished to ensure accurate 1/4 wavefront and <30 seconds parallelism over the both surfaces
- 95% transmission of main nebula emission lines (i.e. H-alpha 656nm, OIII 496nm and 500nm, SII 672nm and H-beta 486nm
- 0.1% transmission of off-band, specifically the major emission lines of artificial light pollution (i.e. Na 589nm, Hg 435nm and 578nm). Transmission of 0.1% is equivalent to OD3(Optical Density), and a high optical density value indicates very low transmission, and low optical density indicates high transmission.
Coating Parameter
Coating Parameter
- Multi-layers anti-reflection coating
- Non-cementing optical substrate coating
- Electron-beam gun evaporation with 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
Filter Cell
- Ultra-thin filter cell minimize vignetting by maximize possible clear aperture (clear aperture is 26mm for 1.25”; 45mm for 2”)
- Aerometal Material
This item is normally shipped by Courier. Estimated shipping cost is:
Nationwide $6.00
Rural Delivery $10.00
Actual shipping cost will depend on the whole order and will be confirmed on your invoice.